Fuse management for an electric mobile application

ABSTRACT

A system including a vehicle having a motive electrical power path; a power distribution unit having a current protection circuit disposed in the motive electrical power path, the current protection circuit including: a first leg of the current protection circuit comprising a first pyro-fuse; a second leg of the current protection circuit comprising a thermal fuse in series arrangement with a second pyro-fuse; and where the first leg and the second leg are coupled in a parallel arrangement; a controller, including: a current detection circuit structured to determine a current flow through the motive electrical power path; and a pyro-fuse activation circuit structured to provide a pyro-fuse activation command in response to the current flow exceeding a threshold current flow value; and where at least one of the first pyro-fuse and the second pyro-fuse is responsive to the pyro-fuse activation command.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/184,185, filed on Nov. 8, 2018, and entitled “POWER DISTRIBUTION UNITAND FUSE MANAGEMENT FOR AN ELECTRIC MOBILE APPLICATION” (EATN-2300-U01).

U.S. patent application Ser. No. 16/184,185 claims priority to thefollowing U.S. Provisional Patent Applications: Ser. No. 62/583,355,filed 8 Nov. 2017, and entitled “ACTIVE/PASSIVE THERMAL PROTECTION OFTEMPERATURE SENSITIVE COMPONENTS” (EATN-2001-P01); Ser. No. 62/583,367,filed 8 Nov. 2017, and entitled “FUSE AND CONTACTOR FOR CIRCUITPROTECTION” (EATN-2002-P01); and Ser. No. 62/583,428, filed 8 Nov. 2017,and entitled “FUSE LIFE EXTENDER METHOD” (EATN-2006-P01).

U.S. patent application Ser. No. 16/184,185 also claims priority to thefollowing Indian Provisional Patent Applications: Serial Number201711039846, filed 8 Nov. 2017, and entitled “FUSE CURRENT MEASUREMENTWITH ACTIVE INJECTION SYSTEM” (EATN-2003-P01-IN); Serial Number201711039847, filed 8 Nov. 2017, and entitled “NULL OFFSET DETECTION ANDDIAGNOSTICS” (EATN-2004-P01-IN); Serial Number 201711039848, filed 8Nov. 2017, and entitled “DIGITAL FILTERS TO MINIMIZE PHASE SHIFT ANDINDUCED HARMONICS” (EATN-2005-P01-IN); Serial Number 201711039849, filed8 Nov. 2017, and entitled “CALIBRATION OF FUSE CURRENT MEASUREMENTS”(EATN-2007-P01-IN); and Serial Number 201711039850, filed 8 Nov. 2017,and entitled “UNIQUE CURRENT INJECTION WAVEFORM TO IMPROVE INJECTIONMEASUREMENT ACCURACY” (EATN-2008-P01-IN).

All of the above patent documents are incorporated herein by referencein their entirety.

FIELD

Without limitation to a particular field of technology, the presentdisclosure is directed to electrical power distribution, and moreparticularly to electronic power distribution for highly variable loadapplications.

BACKGROUND

Electrical power distribution in many applications is subject to anumber of challenges. Applications having a highly variable load, suchas mobile applications or vehicles, subject fuses in the power channelsto rapid swings in power throughput and induce thermal and mechanicalstresses on the fuses. Certain applications have a high cost fordown-time of the application. Certain applications, including mobileapplications, are subject to additional drawbacks from loss of power,such as loss of mobility of the application unexpectedly, including atan inconvenient location, while in traffic, or the like. Electricalsystems in many applications are complex, with multiple components inthe system, and variations in the wiring and environment of theelectrical system, leading to variations in the electrical systemresponse, introduction of noise, variations in system resonantfrequencies, and/or variations in system capacitance and/or inductance,even for nominally identical installations. These complexities introduceadditional challenges for high resolution and/or highly precisedeterminations of the electrical characteristics of aspects of thesystem. Additionally, highly variable and/or mobile systems provideadditional challenges for diagnostics and determinations about aspectsof the electrical system, as highly invasive active determinations maynot be acceptable to application performance, and/or the system may notprovide many opportunities, or only brief opportunities, for makingdeterminations about the electrical system.

SUMMARY

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit having a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including: a first leg of the current protection circuitincluding a pyro-fuse; a second leg of the current protection circuitincluding a thermal fuse; and where the first leg and the second leg arecoupled in a parallel arrangement; a controller, including: a currentdetection circuit structured to determine a current flow through themotive electrical power path; and a pyro-fuse activation circuitstructured to provide a pyro-fuse activation command in response to thecurrent flow exceeding a threshold current flow value; and where thepyro-fuse is responsive to the pyro-fuse activation command.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where a first resistance through the first legand a second resistance through the second leg are configured such thata resulting current through the second leg after the pyro-fuse activatesis sufficient to activate the thermal fuse. An example includes aresistor coupled in a series arrangement with the thermal fuse, suchthat a resulting current through the second leg after the pyro-fuseactivates is below a second threshold current flow value. An examplesystem includes a contactor coupled in a series arrangement with thethermal fuse, the controller further including a contactor activationcircuit structured to provide a contactor open command in response to atleast one of the pyro-fuse activation command or the current flowexceeding the threshold current flow value; and/or a resistor coupled ina series arrangement with the thermal fuse, such that a resultingcurrent through the second leg after the pyro-fuse activates is below asecond threshold current flow value. An example includes a resistorcoupled in a series arrangement with the pyro-fuse, such that aresulting current through the first leg after the thermal fuse activatesis below a second threshold current flow value; and/or a second thermalfuse coupled in a series arrangement with the pyro-fuse, such that aresulting current through the first leg after the thermal fuse activatesis sufficient to activate the second thermal fuse.

An example procedure includes an operation to determine a current flowthrough a motive electrical power path of a vehicle; an operation todirect the current flow through a current protection circuit having aparallel arrangement, with a pyro-fuse on a first leg of the currentprotection circuit and a thermal fuse on a second leg of the currentprotection circuit; and an operation to provide a pyro-fuse activationcommand in response to the current flow exceeding a threshold currentflow value.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to configure a firstresistance through the first leg and a second resistance through thesecond leg such that a resulting current through the second leg afterthe pyro-fuse activates is sufficient to activate the thermal fuse. Anexample procedure includes an operation to configure a second resistancethrough the second leg such that a resulting current through the secondleg after the pyro-fuse activates is below a second threshold currentflow value. An example procedure includes an operation to a contactorcoupled in a series arrangement with the thermal fuse, the procedurefurther including providing a contactor open command in response to atleast one of providing the pyro-fuse activation command or the currentflow exceeding the threshold current flow value; and/or an operation toconfigure a second resistance through the second leg such that aresulting current through the second leg after the pyro-fuse activatesis below a second threshold current flow value. An example procedurefurther including a resistor coupled in a series arrangement with thepyro-fuse such that a resulting current through the first leg after thethermal fuse activates is below a second threshold current flow value;and/or further including a second thermal fuse coupled in a seriesarrangement with the pyro-fuse, such that a resulting current throughthe first leg after the thermal fuse activates is sufficient to activatethe second thermal fuse.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit having a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including: a first leg of the current protection circuitincluding a thermal fuse; a second leg of the current protection circuitincluding a contactor; and where the first leg and the second leg arecoupled in a parallel arrangement; a controller, including: a currentdetection circuit structured to determine a current flow through themotive electrical power path; and a fuse management circuit structuredto provide a contactor activation command in response to the currentflow; and where the contactor is responsive to the contactor activationcommand.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the contactor is open during nominaloperations of the vehicle, and where the fuse management circuit isstructured to provide the contactor activation command as a contactorclosing command in response to determining that the current flow is aabove a thermal wear current for the thermal fuse; and/or where the fusemanagement circuit is further structured to provide the contactoractivation command as the contactor closing command in response todetermining that the current flow is below a current protection valuefor the motive electrical power path. An example system includes wherethe contactor is closed during nominal operations of the vehicle, andwhere the fuse management circuit is structured to provide the contactoractivation command as a contactor opening command in response todetermining that the current flow is above a current protection valuefor the motive electrical power path. An example system includes wherethe fuse management circuit is further structured to provide thecontactor activation command in response to the current flow byperforming at least one operation selected from the operationsconsisting of: responding to a rate of change of the current flow;responding to a comparison of the current flow to a threshold value;responding to one of an integrated or accumulated value of the currentflow; and responding to one of an expected or a predicted value of anyof the foregoing.

An example procedure includes an operation to determine a current flowthrough a motive electrical power path of a vehicle; an operation todirect the current flow through a current protection circuit having aparallel arrangement, with a thermal fuse on a first leg of the currentprotection circuit and a contactor on a second leg of the currentprotection circuit; and an operation to provide a contactor activationcommand in response to the current flow.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to close the contactorin response to the current flow. An example procedure includes anoperation to determine that the current flow is below a currentprotection value for the motive electrical power path before the closingthe contactor. An example procedure includes at least one operationselected from the operations consisting of: responding to a rate ofchange of the current flow; responding to a comparison of the currentflow to a threshold value; responding to one of an integrated oraccumulated value of the current flow; and responding to one of anexpected or a predicted value of any of the foregoing. An exampleprocedure includes an operation to open the contactor in response to thecurrent flow; an operation to determine that the current flow is above acurrent protection value for the motive electrical power path beforeopening the contactor; an operation to open the contactor includingperforming at least one operation selected from the operationsconsisting of: responding to a rate of change of the current flow;responding to a comparison of the current flow to a threshold value;responding to one of an integrated or accumulated value of the currentflow; and responding to one of an expected or a predicted value of anyof the foregoing.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit having a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including: a first leg of the current protection circuitincluding a thermal fuse; a second leg of the current protection circuitincluding a solid state switch; and where the first leg and the secondleg are coupled in a parallel arrangement; a controller, including: acurrent detection circuit structured to determine a current flow throughthe motive electrical power path; and a fuse management circuitstructured to provide a switch activation command in response to thecurrent flow; and where the solid state switch is responsive to theswitch activation command.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes a contactor coupled to the current protectioncircuit, where the contactor in the open position disconnects one of thecurrent protection circuit or the second leg of the current protectioncircuit.

An example procedure includes an operation to determine a current flowthrough a motive electrical power path of a vehicle; an operation todirect the current flow through a current protection circuit having aparallel arrangement, with a thermal fuse on a first leg of the currentprotection circuit and a solid state switch on a second leg of thecurrent protection circuit; and an operation to provide a switchactivation command in response to the current flow.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to close the solid stateswitch in response to the current flow; and/or determine that thecurrent flow is below a current protection value for the motiveelectrical power path before the closing the solid state switch. Anexample procedure includes an operation to close the solid state switchincludes performing at least one operation selected from the operationsconsisting of: responding to a rate of change of the current flow;responding to a comparison of the current flow to a threshold value;responding to one of an integrated or accumulated value of the currentflow; and responding to one of an expected or a predicted value of anyof the foregoing. An example procedure includes an operation to open thesolid state switch in response to the current flow; and/or determinethat the current flow is above a current protection value for the motiveelectrical power path before opening the solid state switch. An exampleprocedure includes an operation to open the solid state switch includesperforming at least one operation selected from the operationsconsisting of: responding to a rate of change of the current flow;responding to a comparison of the current flow to a threshold value;responding to one of an integrated or accumulated value of the currentflow; and responding to one of an expected or a predicted value of anyof the foregoing. An example procedure includes an operation to open acontactor after the opening the solid state switch, where opening thecontactor disconnects one of the current protection circuit or thesecond leg of the current protection circuit.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit having a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including: a first leg of the current protection circuitincluding a first thermal fuse; a second leg of the current protectioncircuit including a second thermal fuse and a contactor; and where thefirst leg and the second leg are coupled in a parallel arrangement; acontroller, including: a current detection circuit structured todetermine a current flow through the motive electrical power path; and afuse management circuit structured to provide a contactor activationcommand in response to the current flow; and where the contactor isresponsive to the contactor activation command.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the contactor is open during nominaloperations of the vehicle, and where the fuse management circuit isstructured to provide the contactor activation command as a contactorclosing command in response to determining that the current flow is aabove a thermal wear current for the first thermal fuse; and/or wherethe fuse management circuit is further structured to provide thecontactor activation command as a contactor closing command in responseto determining that the current flow is below a current protection valuefor the motive electrical power path. An example system includes avehicle operating condition circuit structured to determine an operatingmode for the vehicle, and where the fuse management circuit is furtherstructured to provide the contactor activation command in response tothe operating mode; and/or where the fuse management circuit is furtherstructured to provide the contactor activation command as a contactorclosing command in response to the operating mode including at least oneoperating mode selected from the operating modes consisting of: acharging mode; a high performance mode; a high power request mode; anemergency operation mode; and a limp home mode. An example systemincludes where the contactor is closed during nominal operations of thevehicle, and where the fuse management circuit is structured to providethe contactor activation command as a contactor opening command inresponse to determining that the current flow is above a currentprotection value for the motive electrical power path; where thecontactor is closed during nominal operations of the vehicle, and wherethe fuse management circuit is structured to provide the contactoractivation command as a contactor opening command in response to theoperating mode; and/or where the fuse management circuit is furtherstructured to provide the contactor activation command as a contactoropening command in response to the operating mode including at least oneof an economy mode or a service mode.

An example procedure includes an operation to determine a current flowthrough a motive electrical power path of a vehicle; an operation todirect the current flow through a current protection circuit having aparallel arrangement, with a first thermal fuse on a first leg of thecurrent protection circuit and a second thermal fuse and a contactor ona second leg of the current protection circuit; and an operation toprovide a contactor activation command in response to the current flow.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to close the contactorin response to the current flow being above a thermal wear current forthe first thermal fuse; and/or closing the contactor further in responseto the current flow being below a current protection value for themotive electrical power path. An example procedure includes an operationto determine an operating mode for the vehicle, and providing thecontactor activation command further in response to the operating mode.An example procedure includes an operation to provide the contactoractivation command as a contactor closing command in response to theoperating mode including at least one operating mode selected from theoperating modes consisting of: a charging mode; a high performance mode;a high power request mode; an emergency operation mode; and a limp homemode. An example procedure includes an operation to provide thecontactor activation command as a contactor opening command in responseto determining that the current flow is above a current protection valuefor the motive electrical power path; and/or provide the contactoractivation command as a contactor opening command in response to theoperating mode including at least one of an economy mode or a servicemode.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit having a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including: a first leg of the current protection circuitincluding a first thermal fuse and a first contactor; a second leg ofthe current protection circuit including a second thermal fuse and asecond contactor; and where the first leg and the second leg are coupledin a parallel arrangement; a controller, including: a current detectioncircuit structured to determine a current flow through the motiveelectrical power path; and a fuse management circuit structured toprovide a plurality of contactor activation commands in response to thecurrent flow; and where the first contactor and the second contactor areresponsive to the plurality of contactor activation commands, therebyproviding a selected configuration of the current protection circuit.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the current protection circuit furtherincludes: at least one additional leg, where each additional legincludes an additional thermal fuse and an additional contactor; andwhere each additional contactor is further responsive to the pluralityof contactor activation commands, thereby providing the selectedconfiguration of the current protection circuit. An example systemincludes a vehicle operating condition circuit structured to determinean operating mode for the vehicle, and where the fuse management circuitis further structured to provide the plurality of contactor activationcommands in response to the operating mode; and/or where the fusemanagement circuit is further structured to determine an active currentrating for the motive electrical power path in response to the operatingmode, and to provide the plurality of contactor activation commands inresponse to the active current rating. An example system includes wherethe first leg of the current protection circuit further includes anadditional first contactor in a parallel arrangement with the firstthermal fuse, where the current detection circuit is further structuredto determine a first leg current flow, where the fuse management circuitis further structured to provide the plurality of contactor activationcommands further in response to the first leg current flow, and wherethe additional first contactor is responsive to the plurality ofcontactor activation commands; where the additional first contactor isopen during nominal operations of the vehicle, and where the fusemanagement circuit is structured to provide the plurality of contactoractivation commands including an additional first contactor closingcommand in response to determining that the first leg current flow is aabove a thermal wear current for the first thermal fuse: where the fusemanagement circuit is structured to provide the additional firstcontactor closing command in response to determining at least one of:that the first leg current flow is below a first leg current protectionvalue, or that the current flow is below a motive electrical power pathcurrent protection value; and/or where the additional first contactor isclosed during nominal operations of the vehicle, and where the fusemanagement circuit is structured to provide the plurality of contactoractivation commands including an additional first contactor openingcommand in response to determining at least one of: that the first legcurrent flow is above a first leg current protection value, or that thecurrent flow is above a motive electrical power path current protectionvalue.

An example procedure includes an operation to determine a current flowthrough a motive electrical power path of a vehicle; an operation todirect the current flow through a current protection circuit having aparallel arrangement, with a first thermal fuse and a first contactor ona first leg of the current protection circuit, and a second thermal fuseand a second contactor on a second leg of the current protectioncircuit; and an operation to provide a selected configuration of thecurrent protection circuit in response to the current flow through themotive electrical power path of the vehicle, where providing theselected configuration includes providing a contactor activation commandto each of the first contactor and the second contactor.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure includes an operation further including at least oneadditional leg of the current protection circuit, each additional leg ofthe current protection circuit having an additional thermal fuse and anadditional contactor, and where the providing the selected configurationof the current protection circuit includes providing a contactoractivation command to each additional contactor. An example procedureincludes an operation to determine an operating mode for the vehicle,and providing the selected configuration further in response to theoperating mode; and/or an operation to determine an active currentrating for the motive electrical power path in response to the operatingmode, and where providing the selected configuration of the currentprotection circuit is further in response to the active current rating.An example procedure includes an operation to determine an activecurrent rating for the motive electrical power path, and where providingthe selected configuration of the current protection circuit is furtherin response to the active current rating. An example procedure includesan operation where the first leg of the current protection circuitfurther includes an additional first contactor in a parallel arrangementwith the first thermal fuse, the method further including: determining afirst leg current flow, and where providing the selected configurationfurther includes providing a contactor activation command to theadditional first contactor; an operation to close the additional firstcontactor in response to determining that the first leg current flow isa above a thermal wear current for the first thermal fuse; an operationto close the additional first contactor further in response todetermining at least one of: that the first leg current flow is below afirst leg current protection value, or that the current flow is below amotive electrical power path current protection value; and/or anoperation to open the additional first contactor in response todetermining at least one of: that the first leg current flow is above afirst leg current protection value, or that the current flow is above amotive electrical power path current protection value.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit having a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including a fuse; a controller, including: a fuse status circuitstructured to determine a fuse event value; and a fuse managementcircuit structured to provide a fuse event response based on the fuseevent value.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes a fuse life description circuit structured todetermine a fuse life remaining value, where the fuse event valueincludes a representation that the fuse life remaining value is below athreshold value, and where the fuse management circuit is furtherstructured to provide the fuse event response further based on the fuselife remaining value; where providing the fuse event response includesproviding at least one of a fault code or a notification of the fuseevent value; where providing the fuse event response includes adjustinga maximum power rating for the motive electrical power path; whereproviding the fuse event response includes adjusting a maximum powerslew rate for the motive electrical power path; and/or where providingthe fuse event response includes adjusting a configuration of thecurrent protection circuit. An example system includes where the currentprotection circuit further includes a contactor coupled in a parallelarrangement to the fuse; where the fuse management circuit is furtherstructured to provide a contactor activation command in response to thefuse event value; and where the contactor is responsive to the contactoractivation command Δn example system includes where the fuse managementcircuit is further structured to provide the contactor activationcommand as a contactor closing command in response to the fuse eventvalue including one of a thermal wear event or an imminent thermal wearevent for the fuse. An example system includes where the fuse managementcircuit is further structured to adjust a current threshold value forthe contactor activation command in response to the fuse life remainingvalue; and/or where providing the fuse event response includes adjustinga cooling system interface for a cooling system at least selectivelythermally coupled to the fuse in response to the fuse life remainingvalue.

An example procedure includes an operation to determine a fuse eventvalue for a fuse disposed in a current protection circuit, the currentprotection circuit disposed in a motive electrical power path of avehicle; and an operation to provide a fuse event response based on thefuse event value.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to determine a fuse liferemaining value, where the fuse event value includes a representationthat the fuse life remaining value is below a threshold value, andproviding the fuse event response further based on the fuse liferemaining value; an operation to provide the fuse event responseincludes providing at least one of a fault code or a notification of thefuse event value; an operation to provide the fuse event responseincludes adjusting a maximum power rating for the motive electricalpower path; an operation to provide the fuse event response includesadjusting a maximum power slew rate for the motive electrical powerpath; an operation to provide the fuse event response includes adjustinga configuration of the current protection circuit. An example procedureincludes an operation where the current protection circuit furtherincludes a contactor coupled in a parallel arrangement to the fuse;where the fuse management circuit is further structured to provide acontactor activation command in response to the fuse event value; andwhere the contactor is responsive to the contactor activation command;where the fuse management circuit is further structured to provide thecontactor activation command as a contactor closing command in responseto the fuse event value including one of a thermal wear event or animminent thermal wear event for the fuse; and/or where the fusemanagement circuit is further structured to adjust a current thresholdvalue for the contactor activation command in response to the fuse liferemaining value. An example procedure includes an operation to providethe fuse event response includes adjusting a cooling system interfacefor a cooling system at least selectively thermally coupled to the fusein response to the fuse life remaining value. An example procedureincludes an operation to provide the fuse event response includesproviding at least one of a fault code or a notification of the fuseevent value. An example procedure includes an operation to determine anaccumulated fuse event description in response to the fuse eventresponse, and storing the accumulated fuse event description. An exampleprocedure includes an operation to provide the accumulated fuse eventdescription, where providing the accumulated fuse event descriptionincludes at least one of providing at least one of a fault code or anotification of the accumulated fuse event description; and an operationto provide the accumulated fuse event description in response to atleast one of a service event or a request for the accumulated fuse eventdescription.

An example system includes a vehicle having a motive electrical powerpath and at least one auxiliary electrical power path; a powerdistribution unit having a motive current protection circuit disposed inthe motive electrical power path, the current protection circuitincluding a fuse; and an auxiliary current protection circuit disposedin each of the at least one auxiliary electrical power paths, eachauxiliary current protection circuit including an auxiliary fuse; acontroller, including: a current determination circuit structured tointerpret a motive current value corresponding to the motive electricalpower path, and an auxiliary current value corresponding to each of theat least one auxiliary electrical power paths.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes a motive current sensor electrically coupled tothe motive electrical power path, where the motive current sensor isconfigured to provide the motive current value. An example systemincludes at least one auxiliary current sensor each electrically coupledto one of the at least one auxiliary electrical power paths, eachauxiliary current sensor configured to provide the correspondingauxiliary current value. An example system includes where the controllerfurther includes a vehicle interface circuit, the vehicle interfacecircuit structured to provide the motive current value to a vehiclenetwork; where the vehicle interface circuit is further structured toprovide the auxiliary current value corresponding to each of the atleast one auxiliary electrical power paths to the vehicle network;and/or further including a battery management controller configured toreceive the motive current value from the vehicle network.

An example procedure includes an operation to provide a powerdistribution unit having a motive current protection circuit and atleast one auxiliary current protection circuit; an operation to power avehicle motive electrical power path through the motive currentprotection circuit; an operation to power at least one auxiliary loadthrough a corresponding one of the at least one auxiliary currentprotection circuit; an operation to determine a motive current valuecorresponding to the motive electrical power path; and an operation todetermine an auxiliary current value corresponding to each of the atleast one auxiliary current protection circuits.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to provide the motivecurrent value to a vehicle network; and/or an operation to receive themotive current value with a battery management controller.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit having a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including: a thermal fuse; a contactor in a series arrangementwith the thermal fuse; and a controller, including: a current detectioncircuit structured to determine a current flow through the motiveelectrical power path; and a fuse management circuit structured toprovide a contactor activation command in response to the current flow;and where the contactor is responsive to the contactor activationcommand.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the thermal fuse includes a current ratingthat is higher than a current corresponding to a maximum powerthroughput of the motive electrical power path. An example systemincludes where the thermal fuse includes a current rating that is higherthan a current corresponding to a quick charging power throughput of themotive electrical power path. An example system includes where thecontactor includes a current rating that is higher than a currentcorresponding to a maximum power throughput of the motive electricalpower path. An example system includes where the contactor includes acurrent rating that is higher than a current corresponding to a quickcharging power throughput of the motive electrical power path. Anexample system includes where the fuse management circuit is furtherstructured to provide the contactor activation command as a contactoropening command in response to the current flow indicating a motiveelectrical power path protection event; and/or where the currentdetection circuit is further structured to determine the motiveelectrical power path protection event by performing at least oneoperation selected from the operations consisting of: responding to arate of change of the current flow; responding to a comparison of thecurrent flow to a threshold value; responding to one of an integrated oraccumulated value of the current flow; and responding to one of anexpected or a predicted value of any of the foregoing.

An example procedure includes an operation to power a motive electricalpower path of a vehicle through a current protection circuit including athermal fuse and a contactor in a series arrangement with the thermalfuse; an operation to determine a current flow through the motiveelectrical power path; and an operation to selectively open thecontactor in response to the current flow.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to provide the thermalfuse having a current rating that is higher than a current correspondingto a maximum power throughput of the motive electrical power path. Anexample procedure includes an operation to provide the thermal fusehaving a current rating that is higher than a current corresponding to aquick charging power throughput of the motive electrical power path. Anexample procedure includes an operation to provide the contactor havinga current rating that is higher than a current corresponding to amaximum power throughput of the motive electrical power path. An exampleprocedure includes an operation to provide the contactor having acurrent rating that is higher than a current corresponding to a quickcharging power throughput of the motive electrical power path. Anexample procedure includes an operation to open the contactor is furtherin response to at least one of: a rate of change of the current flow; acomparison of the current flow to a threshold value; one of anintegrated or accumulated value of the current flow; and an expected orpredicted value of any of the foregoing.

An example procedure includes an operation to power a motive electricalpower path of a vehicle through a current protection circuit including athermal fuse and a contactor in a series arrangement with the thermalfuse; an operation to determine a current flow through the motiveelectrical power path; an operation to open the contactor in response tothe current flow exceeding a threshold value; an operation to confirmthat vehicle operating conditions allow for a re-connection of thecontactor; and an operation to command the contactor to close inresponse to the vehicle operating conditions.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to confirm the vehicleoperating conditions includes at least one vehicle operating conditionselected from the conditions consisting of: an emergency vehicleoperating condition; a user override vehicle operating condition; aservice event vehicle operating condition; and a re-connection commandcommunicated on a vehicle network. An example procedure includes anoperation to monitor the motive electrical power path during thecommanding the contactor to close, and re-opening the contactor inresponse to the monitoring. An example procedure includes an operationto determine an accumulated contactor open event description in responseto the opening the contactor; an operation to prevent the commanding thecontactor to close in response to the accumulated contactor open eventdescription exceeding a threshold value; and/or an operation to adjustthe accumulated contactor open event description in response to thecurrent flow during the opening the contactor. An example procedureincludes an operation to diagnose a welded contactor in response to oneof the current flow during the opening the contactor, and a monitoringof the motive electrical power path during the commanding the contactorto close. An example procedure includes an operation to diagnose awelded contactor in response to a monitoring of at least one of acontactor actuator position, a contactor actuator response, or themotive electrical power path during the opening the contactor; and/or anoperation to prevent the commanding the contactor to close in responseto the diagnosed welded contactor.

An example apparatus includes a motive electrical power currentprotection circuit structured to: determine a current flow through amotive electrical power path of a vehicle; and open a contactor disposedin a current protection circuit including a thermal fuse and thecontactor in a series arrangement with the thermal fuse in response tothe current flow exceeding a threshold value; a vehicle re-power circuitstructured to: confirm that vehicle operating conditions allow for are-connection of the contactor; and close the contactor in response tothe vehicle operating conditions.

Certain further aspects of an example apparatus are described following,any one or more of which may be present in certain embodiments. Anexample apparatus includes where the vehicle re-power circuit is furtherstructured to confirm the vehicle operating conditions by confirming atleast one vehicle operating condition selected from the conditionsconsisting of: an emergency vehicle operating condition; a user overridevehicle operating condition; a service event vehicle operatingcondition; and a re-connection command communicated on a vehiclenetwork. An example apparatus includes where the motive electrical powercurrent protection circuit is further structured to monitor the motiveelectrical power path during the closing the contactor to close, andwhere the vehicle re-power circuit is further structured to re-open thecontactor in response to the monitoring. An example apparatus includes acontactor status circuit structured to determine an accumulatedcontactor open event description in response to the opening thecontactor; where the vehicle re-power circuit is further structured toprevent the closing the contactor in response to the accumulatedcontactor open event description exceeding a threshold value; and/orwhere the contactor status circuit is further structured to adjust theaccumulated contactor open event description in response to the currentflow during the opening the contactor. An example apparatus includes acontactor status circuit structured to diagnose a welded contactor inresponse to one of, during the commanding the contactor to close: thecurrent flow during the opening the contactor; and a monitoring of themotive electrical power path by the motive electrical power currentprotection circuit. An example apparatus includes a contactor statuscircuit structured to diagnose a welded contactor in response to amonitoring of, during the opening of the contactor, at least one of: acontactor actuator position by the vehicle re-power circuit; a contactoractuator response by the vehicle re-power circuit; and the motiveelectrical power path by the motive electrical power current protectioncircuit; and/or where the contactor status circuit is further structuredto prevent the closing the contactor in response to the diagnosed weldedcontactor.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit including: a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including a thermal fuse and a contactor in a series arrangementwith the thermal fuse; a high voltage power input coupling including afirst electrical interface for a high voltage power source; a highvoltage power output coupling including a second electrical interfacefor a motive power load; and where the current protection circuitelectrically couples the high voltage power input to the high voltagepower output, and where the current protection circuit is at leastpartially disposed in a laminated layer of the power distribution unit,the laminated layer including an electrically conductive flow pathdisposed two electrically insulating layers.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where current protection circuit includes amotive power bus bar disposed in the laminated layer of the powerdistribution unit. An example system includes where the vehicle furtherincludes an auxiliary electrical power path; where the powerdistribution unit further includes: an auxiliary current protectioncircuit disposed in the auxiliary electrical power path, the auxiliarycurrent protection circuit including a second thermal fuse; an auxiliaryvoltage power input coupling including a first auxiliary electricalinterface for a low voltage power source; an auxiliary voltage poweroutput coupling including a second auxiliary electrical interface for aan auxiliary load; and where the auxiliary current protection circuitelectrically couples the auxiliary voltage power input to the auxiliaryvoltage power output, and where the auxiliary current protection circuitis at least partially disposed in the laminated layer of the powerdistribution unit. An example system includes where the laminated layerof the power distribution unit further includes at least one thermallyconductive flow path disposed between two thermally insulating layers;where the at least one thermally conductive flow path is configured toprovide thermal coupling between a heat sink, and a heat source, wherethe heat source includes at least one of the contactor, the thermalfuse, and the second thermal fuse; where the heat sink includes at leastone of a thermal coupling to an active cooling source and a housing ofthe power distribution unit; and/or further including a thermal conduitdisposed between the at least one thermally conductive flow path and theheat source.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit including a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including a thermal fuse and a contactor in a series arrangementwith the thermal fuse; a current source circuit electrically coupled tothe thermal fuse and structured to inject a current across the thermalfuse; and a voltage determination circuit electrically coupled to thethermal fuse and structured to determine at least one of an injectedvoltage amount and a thermal fuse impedance value.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the motive electrical power path includesa direct current power path; where the current source circuit includesat least one of an alternating current source and a time varying currentsource, further including a hardware filter electrically coupled to thethermal fuse, the hardware filter configured in response to an injectionfrequency of the current source circuit; where the hardware filterincludes a high pass filter having a cutoff frequency determined inresponse to the injection frequency of the current source circuit; wherethe hardware filter includes a low pass filter having a cutoff frequencydetermined in response to at least one of the injection frequency of thecurrent source circuit or a load change value of the motive electricalpower path; where the hardware filter includes a low pass filter havinga cutoff frequency determined in response to at least one of theinjection frequency of the current source circuit or a load change valueof the motive electrical power path; where the voltage determinationcircuit is further structured to determine to determine an injectedvoltage drop of the thermal fuse in response to an output of the highpass filter; where the voltage determination circuit is furtherstructured to determine the thermal fuse impedance value in response tothe injected voltage drop; and/or where the voltage determinationcircuit is further structured to determine a load voltage drop of thethermal fuse in response to an output of the low pass filter, the systemfurther including a load current circuit structured to determine a loadcurrent through the fuse in response to the thermal fuse impedancevalue, and further in response to the load voltage drop.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit including a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including a thermal fuse and a contactor in a series arrangementwith the thermal fuse; a current source circuit electrically coupled tothe thermal fuse and structured to inject a current across the thermalfuse; a voltage determination circuit electrically coupled to thethermal fuse and structured to determine at least one of an injectedvoltage amount and a thermal fuse impedance value, where the voltagedetermination circuit includes a high pass filter having a cutofffrequency selected in response to a frequency of the injected current.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the voltage determination circuit furtherincludes a bandpass filter having a bandwidth selected to bound thefrequency of the injected current. An example system includes where thehigh pass filter includes an analog hardware filter, and where thebandpass filter includes a digital filter. An example system includeswhere the high pass filter and the bandpass filter comprise digitalfilters; where the voltage determination circuit is further structuredto determine the thermal fuse impedance value in response to theinjected voltage drop; and/or further including a fuse characterizationcircuit structured to store one of a fuse resistance value and a fuseimpedance value, and where the fuse characterization circuit is furtherstructured to update the stored one of the fuse resistance value and thefuse impedance value in response to the thermal fuse impedance value. Anexample system includes where the fuse characterization circuit isfurther structured to update the stored one of the fuse resistance valueand the fuse impedance value by performing at least one operationselected from the operations consisting of: updating a value to thethermal fuse impedance value; filtering a value using the thermal fuseimpedance value as a filter input; rejecting the thermal fuse impedancevalue for a period of time or for a number of determinations of thethermal fuse impedance value; and updating a value by performing arolling average of a plurality of thermal impedance values over time. Anexample system includes where the power distribution unit furtherincludes a plurality of thermal fuses disposed therein, and where thecurrent source circuit is further electrically coupled to the pluralityof thermal fuses, and to sequentially inject a current across each ofthe plurality of thermal fuses; and where the voltage determinationcircuit is further electrically coupled to each of the plurality ofthermal fuses, and further structured to determine at least one of aninjected voltage amount a thermal fuse impedance value for each of theplurality of thermal fuses; where the current source circuit is furtherstructured to sequentially inject the current across each of theplurality of thermal fuses in a selected order of the fuses; where thecurrent source circuit is further structured to adjust the selectedorder in response to at least one of: a rate of change of a temperatureof each of the fuses; an importance value of each of the fuses; acriticality of each of the fuses; a power throughput of each of thefuses; and one of a fault condition or a fuse health condition of eachof the fuses; and/or where the current source circuit is furtherstructured to adjust the selected order in response to one of a plannedduty cycle and an observed duty cycle of the vehicle. An example systemincludes where the current source circuit is further structured to sweepthe injected current through a range of injection frequencies; where thecurrent source circuit is further structured to inject the currentacross the thermal fuse at a plurality of injection frequencies. Anexample system includes where the current source circuit is furtherstructured to inject the current across the thermal fuse at a pluralityof injection voltage amplitudes. An example system includes where thecurrent source circuit is further structured to inject the currentacross the thermal fuse at an injection voltage amplitude determined inresponse to a power throughput of the thermal fuse. An example systemincludes where the current source circuit is further structured toinject the current across the thermal fuse at an injection voltageamplitude determined in response to a duty cycle of the vehicle.

An example procedure includes an operation to determine null offsetvoltage for a fuse current measurement system, including an operation todetermine that no current is demanded for a fuse load for a fuseelectrically disposed between an electrical power source and anelectrical load; an operation to determine a null offset voltage inresponse to no current demanded for the fuse load; and an operation tostore the null offset voltage.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to update a stored nulloffset voltage in response to the determined null offset voltage. Anexample procedure includes an operation to diagnose a component inresponse to the null offset voltage; and/or an operation to determinewhich one of a plurality of components is contributing to the nulloffset voltage. An example procedure includes an operation to determinethat no current is demanded for the fuse load includes at least oneoperation selected from the operations consisting of an operation todetermine that a key-off event has occurred for a vehicle including thefuse, the electrical power source, and the electrical load; an operationto determine that a key-on event has occurred for the vehicle; andoperation to determine that the vehicle is powering down; and anoperation to determine that the vehicle is in an accessory condition,where the vehicle in the accessory condition does not provide powerthrough the fuse.

An example apparatus to determine offset voltage to adjust a fusecurrent determination includes a fuse load circuit structured todetermine that no current is demanded for a fuse load, and to furtherdetermine that contactors associated with the fuse are open; an offsetvoltage determination circuit structured to determine an offset voltagecorresponding to at least one component in a fuse circuit associatedwith the fuse, in response to the determining that no current isdemanded for the fuse load; and an offset data management circuitstructured to store the offset voltage, and to communicate a currentcalculation offset voltage for use by a controller to determine currentflow through the fuse.

An example procedure includes an operation to provide digital filtersfor a fuse circuit in power distribution unit, including an operation toinject an alternating current across a fuse, the fuse electricallydisposed between an electrical power source and an electrical load; anoperation to determine the base power through a fuse by performing alow-pass filter operation on one of a measured current value and ameasured voltage value for the fuse; and an operation to determine aninjected current value by performing a high-pass filter operation on oneof the measured current value and the measured voltage value for thefuse.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to adjust parameters ofat least one of the low-pass filter and the high-pass filter in responseto a duty cycle of one of power and current through the fuse. An exampleprocedure includes an operation to sweep the injected alternatingcurrent through a range of injection frequencies. An example procedureincludes an operation to inject the alternating current across the fuseat a plurality of injection frequencies. An example procedure includesan operation where the current source circuit is further structured toinject the current across the fuse at a plurality of injection voltageamplitudes. An example procedure includes an operation where the currentsource circuit is further structured to inject the current across thefuse at an injection voltage amplitude determined in response to a powerthroughput of the fuse.

An example procedure includes an operation to calibrate a fuseresistance determination algorithm, including: an operation to store aplurality of calibration sets corresponding to a plurality of duty cyclevalues, the duty cycles including an electrical throughput valuecorresponding to a fuse electrically disposed between an electricalpower source and an electrical load; where the calibration sets includecurrent source injection settings for a current injection deviceoperationally coupled to the fuse; an operation to determine a dutycycle of a system including the fuse, the electrical power source, andthe electrical load; an operation to determine injection settings forthe current injection device in response to the plurality of calibrationsets and the determined duty cycle; and an operation to operate thecurrent injection device in response to the determined injectionsettings.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation where the calibrationsets further comprise filter settings for at least one digital filter,where the method further includes determining the fuse resistanceutilizing the at least one digital filter.

An example procedure includes an operation to 1. A method to provideunique current waveforms to improve fuse resistance measurement for apower distribution unit, including: confirming that contactorselectrically positioned in a fuse circuit are open, where the fusecircuit includes a fuse electrically disposed between an electricalpower source and an electrical load; determining a null voltage offsetvalue for the fuse circuit; conducting a plurality of current injectionsequences across the fuse, each of the current injection sequencesincluding a selected current amplitude, current frequency, and currentwaveform value; determining a fuse resistance value in response to thecurrent injection sequences and the null voltage offset value.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to adjust filteringcharacteristics for a digital filter in response to each of theplurality of current injection sequences, and measuring one of the fusecircuit voltage and the fuse circuit current with the digital filterduring the corresponding one of the plurality of current injectionsequences using the adjusted filtering characteristics.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit including a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including a thermal fuse and a contactor in a series arrangementwith the thermal fuse; a current source circuit electrically coupled tothe thermal fuse and structured to inject a current across the thermalfuse; a voltage determination circuit electrically coupled to thethermal fuse and structured to determine an injected voltage amount anda thermal fuse impedance value, where the voltage determination circuitis structured to perform a frequency analysis operation to determine theinjected voltage amount.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the voltage determination circuit isfurther structured to determine the injected voltage amount bydetermining an amplitude of a voltage across the fuse at a frequency ofinterest; and/or where the frequency of interest is determined inresponse to a frequency of the injected voltage. An example systemincludes where the current source circuit is further structured to sweepthe injected current through a range of injection frequencies. Anexample system includes where the current source circuit is furtherstructured to inject the current across the thermal fuse at a pluralityof injection frequencies. An example system includes where the currentsource circuit is further structured to inject the current across thethermal fuse at a plurality of injection voltage amplitudes. An examplesystem includes where the current source circuit is further structuredto inject the current across the thermal fuse at an injection voltageamplitude determined in response to a power throughput of the thermalfuse. An example system includes where the current source circuit isfurther structured to inject the current across the thermal fuse at aninjection voltage amplitude determined in response to a duty cycle ofthe vehicle.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit including a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including a thermal fuse and a contactor in a series arrangementwith the thermal fuse; a current source circuit electrically coupled tothe thermal fuse and structured to determine that a load powerthroughput of the motive electrical power path is low, and to inject acurrent across the thermal fuse in response to the load power throughputof the motive electrical power path being low; a voltage determinationcircuit electrically coupled to the thermal fuse and structured todetermine at least one of an injected voltage amount and a thermal fuseimpedance value, where the voltage determination circuit includes a highpass filter having a cutoff frequency selected in response to afrequency of the injected current.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the current source circuit is furtherstructured to determine the load power throughput of the motiveelectrical power path is low in response to the vehicle being in ashutdown state. An example system includes where the current sourcecircuit is further structured to determine the load power throughput ofthe motive electrical power path is low in response to the vehicle beingin a keyoff state. An example system includes where the current sourcecircuit is further structured to determine the load power throughput ofthe motive electrical power path is low in response to a motive torquerequest for the vehicle being zero. An example system includes where thepower distribution unit further includes a plurality of fuses, and wherethe current source circuit is further structured to inject the currentacross each of the plurality of fuses in a selected sequence; and/orwhere the current source circuit is further structured to inject thecurrent across a first one of the plurality of fuses at a first shutdownevent of the vehicle, and to inject the current across a second one ofthe plurality of fuses at a second shutdown event of the vehicle.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit including a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including a thermal fuse and a contactor in a series arrangementwith the thermal fuse; a current source circuit electrically coupled tothe thermal fuse and structured to inject a current across the thermalfuse; a voltage determination circuit electrically coupled to thethermal fuse and structured to determine at least one of an injectedvoltage amount and a thermal fuse impedance value, where the voltagedetermination circuit includes a high pass filter having a cutofffrequency selected in response to a frequency of the injected current;and a fuse status circuit structured to determine a fuse condition valuein response to the at least one of the injected voltage amount and thethermal fuse impedance value.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the fuse status circuit is furtherstructured to provide the fuse condition value by providing at least oneof a fault code or a notification of the fuse condition value; where thefuse status circuit is further structured to adjust a maximum powerrating for the motive electrical power path in response to the fusecondition value; where the fuse status circuit is further structured toadjust a maximum power slew rate for the motive electrical power path inresponse to the fuse condition value; where the fuse status circuit isfurther structured to adjust a configuration of the current protectioncircuit in response to the fuse condition value; where the powerdistribution unit further includes an active cooling interface, andwhere the fuse status circuit is further structured to adjust the activecooling interface in response to the fuse condition value; where thefuse status circuit is further structured to clear the at least one ofthe fault code or the notification of the fuse condition value inresponse to the fuse condition value indicating that the fuse conditionhas improved; where the fuse status circuit is further structured toclear the at least one of the fault code or the notification of the fusecondition value in response to a service event for the fuse; where thefuse status circuit is further structured to determine a fuse liferemaining value in response to the fuse condition value; where the fusestatus circuit is further structured to determine the fuse liferemaining value further in response to a duty cycle of the vehicle;and/or where the fuse status circuit is further structured to determinethe fuse life remaining value further in response to one of an adjustedmaximum power rating for the motive electrical power path or an adjustedmaximum power slew rate for the motive electrical power path.

An example system includes a vehicle having a motive electrical powerpath; a power distribution unit including a current protection circuitdisposed in the motive electrical power path, the current protectioncircuit including a thermal fuse and a contactor in a series arrangementwith the thermal fuse; a fuse thermal model circuit structured todetermine a fuse temperature value of the thermal fuse, and to determinea fuse condition value in response to the fuse temperature value.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes a current source circuit electrically coupled tothe thermal fuse and structured to inject a current across the thermalfuse; a voltage determination circuit electrically coupled to thethermal fuse and structured to determine at least one of an injectedvoltage amount and a thermal fuse impedance value, where the voltagedetermination circuit includes a high pass filter having a cutofffrequency selected in response to a frequency of the injected current;and where the fuse thermal model circuit is structured to determine thefuse temperature value of the thermal fuse further in response to the atleast one of the injected voltage amount and the thermal fuse impedancevalue. An example system includes where the fuse thermal model circuitis further structured to determine the fuse condition value by countinga number of thermal fuse temperature excursion events; and/or where thethermal fuse temperature excursion events each comprise a temperaturerise threshold value within a time threshold value. An example systemincludes where the fuse thermal model circuit is further structured todetermine the fuse condition value by integrating the fuse temperaturevalue; and/or where the fuse thermal model circuit is further structuredto determine the fuse condition value by integrating the fusetemperature value above a temperature threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 shows an embodiment system schematically depicting a powerdistribution unit (PDU) operationally positioned between a power sourceand a load.

FIG. 2 depicts a more detailed embodiment system schematically depictinga PDU.

FIG. 3 depicts a non-limiting example response curve for a fuse.

FIG. 4 depicts a non-limiting example system for mobile application suchas a vehicle.

FIG. 5 depicts a non-limiting example system including a PDU.

FIG. 6 depicts an embodiment apparatus including all or portions of aPDU.

FIG. 7 shows a non-limiting example of interactions between a main fuseand laminated layers.

FIG. 8 shows closer detail of a non-limiting example of interactionsbetween a main fuse and laminated layers.

FIG. 9 depicts an embodiment detailed view of a side section of thelaminated layers.

FIG. 10 shows a top view of a non-limiting example apparatus.

FIG. 11 shows an alternate side view of a non-limiting exampleapparatus.

FIG. 12 depicts an embodiment configuration showing a main fuse coupledto laminated layers on a bottom side of the main fuse.

FIG. 13 depicts an embodiment configuration showing a main fuse coupledto laminated layers on a bottom side of the main fuse with thermal fins.

FIG. 14 depicts an embodiment configuration showing a main fuse coupledto laminated layers on a bottom side of the main fuse with features forenhanced heat flow.

FIG. 15 depicts an alternate embodiment configuration showing a mainfuse coupled to laminated layers on a bottom side of the main fuse withfeatures for heat flow.

FIG. 16 depicts an alternate embodiment configuration showing a mainfuse coupled to laminated layers on a bottom side of the main fuse withfeatures for heat flow.

FIG. 17 depicts an alternate embodiment configuration showing a mainfuse coupled to laminated layers on a bottom side of the main fuse withfeatures for heat flow.

FIG. 18 shows a non-limiting example system including a PDU positionedwithin a battery pack housing or enclosure.

FIG. 19 shows a non-limiting example system including a PDU in a coolantloop for a heat transfer system.

FIG. 20 shows a non-limiting example apparatus for providing additionalprotection against fuse nuisance faults and system failures.

FIG. 21 depicts an embodiment illustrative data for implementing asystem response value.

FIG. 22 depicts a non-limiting example apparatus to measure currentthrough a fuse utilizing active current injection.

FIG. 23 depicts a non-limiting example apparatus to determine a nulloffset voltage and/or diagnose a system component.

FIG. 24 depicts a non-limiting example apparatus to provide for digitalfiltering of a current measurement through a fuse circuit.

FIG. 25 depicts a non-limiting example fuse circuit that may be presenton a PDU.

FIG. 26 depicts an embodiment of a fuse circuit with a contactor.

FIG. 27 depicts an embodiment fuse circuit including a plurality offuses.

FIG. 28 depicts a fuse circuit with fuses in parallel with a contactor.

FIG. 29 depicts illustrative data showing a fuse response to a drivecycle for a vehicle.

FIG. 30 depicts a non-limiting example system including a power sourceand s load with a fuse electrically disposed between the load and thesource.

FIG. 31 depicts a non-limiting example apparatus to determine an offsetvoltage to adjust a fuse current determination.

FIG. 32 depicts a non-limiting example apparatus is depicted to provideunique current waveforms to improve fuse resistance measurement for aPDU.

FIG. 33 depicts a non-limiting example procedure to provide uniquecurrent waveforms to improve fuse resistance measurement for a PDU.

FIG. 34 depicts a non-limiting example procedure to conduct a number ofinjection sequences.

FIG. 35 depicts an illustrative injection characteristic for an exampletest.

FIG. 36 depicts a schematic diagram of a vehicle having a PDU.

FIG. 37 depicts a schematic flow diagram of a procedure to utilize aparallel thermal fuse and pyro-fuse.

FIG. 38 depicts a schematic diagram of a vehicle having a PDU.

FIG. 39 depicts a schematic flow diagram of a procedure to operate athermal fuse bypass.

FIG. 40 depicts a schematic diagram of a vehicle having a PDU.

FIG. 41 depicts a schematic flow diagram of a procedure to operate athermal fuse bypass.

FIG. 42 depicts a schematic diagram of a vehicle having a PDU.

FIG. 43 depicts a schematic flow diagram of a procedure to operateparallel thermal fuses.

FIG. 44 depicts a schematic diagram of a vehicle having a PDU.

FIG. 45 depicts a schematic flow diagram of a procedure to selectivelyconfigure a current protection circuit.

FIG. 46 depicts a schematic diagram of a vehicle having a PDU.

FIG. 47 depicts a schematic flow diagram of a procedure to determine afuse event value, and to respond thereto.

FIG. 48 depicts a schematic diagram of a vehicle having a PDU.

FIG. 49 depicts a schematic flow diagram of a procedure to determinecurrent flow through a number of fuses.

FIG. 50 depicts a schematic diagram of a vehicle having a PDU.

FIG. 51 depicts a schematic flow diagram of a procedure to operate athermal fuse in series with a contactor.

FIG. 52 depicts a schematic flow diagram of a procedure to re-connect acontactor.

FIG. 53 depicts a schematic diagram of a vehicle having a PDU.

FIG. 54 depicts a schematic diagram of a vehicle having a PDU.

FIG. 55 depicts a schematic diagram of a vehicle having a PDU.

FIG. 56 depicts a schematic flow diagram of a procedure to determine anull offset voltage.

FIG. 57 depicts a schematic diagram of an apparatus for determining anoffset voltage.

FIG. 58 depicts a schematic flow diagram of a procedure to determine aninjected current value.

FIG. 59 depicts a schematic flow diagram of a procedure to calibrate afuse resistance algorithm.

FIG. 60 depicts a schematic flow diagram of a procedure to determine afuse resistance using a unique current waveform.

FIG. 61 depicts a schematic diagram of a vehicle having a currentprotection circuit.

FIG. 62 depicts a schematic diagram of a vehicle having a currentprotection circuit.

FIG. 63 depicts a schematic diagram of a vehicle having a currentprotection circuit.

DETAILED DESCRIPTION

Referencing FIG. 1, an example system 100 is schematically depictedincluding a power distribution unit (PDU) 102 operationally positionedbetween a power source 104 and a load 106. The power source 104 may beany type—including at least a battery, generator, and/or capacitor. Thepower source 104 may include multiple sources or lines of power, whichmay be distributed according to the type of power (e.g., a battery inputseparated from a generator input) and/or may be distributed according tothe devices powered (e.g., auxiliary and/or accessory power separatedfrom main load power such as motive force power, and/or divisions withinthe accessories, divisions within the motive force power, etc.). Theload 106 may be any type, including one or more motive force loads(e.g., to individual drive wheel motors, to a global motive drive motor,etc.), one or more accessories (e.g., on-vehicle accessories such assteering, fan, lights, cab power, etc.). In certain embodiments, the PDU102 provides for ease of integration of the electrical system of theapplication including the system 100, such as by utilizing uniform inputand output access, grouping all power distribution into a single box,single area, and/or to a single logically integrated group ofcomponents. In certain embodiments, the PDU 102 provides for protectionof the electrical system, including fusing and/or connection ordisconnection (manual and/or automated) of the electrical system orindividual aspects of the electrical system. In certain embodiments, oneor more power sources 104 may be high voltage (e.g., motive powersources, which may be 96V, 230V-360V, 240V, 480V, or any other value) orlow voltage (e.g., 12V, 24V, 42V, or any other value). In certainembodiments, one or more power sources 104 may be a direct current (DC)power source or an alternating current (AC) power source, includingmulti-phase (e.g., three phase) AC power. In certain embodiments, thePDU 102 is a pass-through device, providing power to the load 106approximately as configured by the power source 104—for example only asaffected by sensing and other operations from the PDU 102 that are notprovided for power configuration. In certain embodiments, the PDU 102may include power electronics, for example rectifying, adjustingvoltage, cleaning up noisy electrical power, etc. to provide selectedelectrical power characteristics to the load 106.

Referencing FIG. 2, a more detailed view of an example PDU 102 isschematically depicted. The example PDU 102 includes a main power source202 (e.g., high voltage, main load power, motive power, etc.) which maybe provided by one or more power sources 104, and an auxiliary powersource 204 (e.g., auxiliary, accessory, low voltage, etc.) which may beprovided by one or more power sources 104. The example PDU 102 depicts asingle main power source 202 and a single auxiliary power source 204,but a given application may include one or more main power sources 202,and may include separated auxiliary power sources 204 and/or omitauxiliary power sources 204.

The example PDU 102 further includes a coolant inlet 206 and a coolantoutlet 204. The provision of coolant to the PDU 102 is optional and maynot be included in certain embodiments. The coolant may be of any typeaccording to availability in the application, including for example anon-vehicle coolant available (e.g., engine coolant, transmissioncoolant, a coolant stream associated with an auxiliary device or otherpower components such as a power source 104, etc.) and/or may be acoolant dedicated to the PDU 102. Where present, the amount of coolingprovided by the coolant may be variable—for example by changing anamount of coolant flowing through a coolant loop through the PDU102—such as by operating hardware (e.g. a valve or restriction) withinthe PDU 102, providing a request for a coolant flow rate to anotherdevice in the system, etc.

The example PDU 102 further includes a main power outlet 210 and anauxiliary power outlet 212. As described preceding, the PDU 102 mayinclude multiple main power outlets 210, and/or divided, multiple,multiplexed, and/or omitted auxiliary power outlets 212. The example PDU102 is a pass-through power device where, except for effects on thepower due to sensing and/or active diagnostics, the power outlets 210,212 have approximately the same electrical characteristics of thecorresponding power inlets 202, 204. However, the PDU 102 can includepower electronics (solid state or otherwise) to configure power in anydesired manner.

The example PDU 102 further includes a controller 214 configured tofunctionally execute certain operations of the PDU 102. The controller214 includes and/or is communicatively coupled to one or more sensorsand/or actuators in the PDU 102, for example to determine currentvalues, voltage values, and/or temperatures of any power source orinput, fuse, connector, or other device in the PDU 102. Additionally oralternatively, the controller 214 is communicatively coupled to thesystem 100 including the PDU 102, including for example a vehiclecontroller, engine controller, transmission controller, applicationcontroller, and/or network device or server (e.g., a fleet computer,cloud server, etc.). The controller 214 may be coupled to an applicationnetwork (e.g., a CAN, a datalink, a private or public network, etc.), anoutside network, and/or another device (e.g., an operator's portabledevice, an in-cab computer for a vehicle, etc.). The controller 214 isdepicted schematically as a single stand-alone device for convenience ofillustration. It will be understood that the controller 214 and/oraspects of the controller 214 may be distributed across multiplehardware devices, included within another hardware device (e.g., acontroller for the power source, load, vehicle, application, etc.),and/or configured as hardware devices, logic circuits, or the like toperform one or more operations of the controller 214. The PDU 102 isdepicted schematically as a device within a single enclosure, but may bewithin a single enclosure and/or distributed in two or more placeswithin an application. In certain embodiments, the inclusion of the PDU102 within a single enclosure provides certain advantages forintegration, reduction of footprint, and/or simplification ofinterfaces. Additionally or alternatively, inclusion of the PDU 102 inmore than one location in an application is contemplated herein, and/orthe inclusion of more than one PDU 102 within an application iscontemplated herein.

The example PDU 102 includes a main contactor 216 selectivelycontrolling the main power throughput of the PDU 102. In the example,the main contactor 216 is communicatively coupled to and controlled bythe controller 214. The main contactor 216 may additionally becontrollable manually, and/or other main contactors 216 may be in-linefor the main power that are controllable manually Δn example maincontactor 216 includes a solenoid (or other coil-based) contactor, suchthat energizing the solenoid provides for either connected main power(e.g., normally open, or power is disconnected when not energized)and/or energizing the solenoid provides for disconnected main power(e.g., normally closed, or power is connected when not energized). Thecharacteristics of the system 100, including design choices aboutwhether power should be active when controller 214 power fails,servicing plans, regulations and/or policies in place, the consequencesof power loss for the system 100, the voltage typically carried on themain power source, the availability of a positive manual disconnectoption, and the like, may inform or dictate the decision of whether themain contactor 216 is normally open or normally closed. In certainembodiments, the main contactor 216 may be a solid state device such asa solid state relay. Where more than one main contactor 216 is present,the various contactors may include the same or distinct hardware (e.g.,one is a solenoid and one is a solid state relay), and/or may includethe same or distinct logic for being normally open or normally closed.The main contactor 216 may be additionally controllable by devicesoutside the PDU 102—for example a keyswitch lockout, another controllerin the system 100 having access to control the main contactor 216, etc.,and/or the controller 214 may be responsive to outside commands to openor close the main contactor 216, and/or additional contactors in-linefor the main power may be responsive to devices outside the PDU 102.

The example PDU 102 includes an auxiliary contactor 218 selectivelycontrolling the auxiliary power throughput of the PDU 102. In theexample, the auxiliary contactor 218 is communicatively coupled to andcontrolled by the controller 214. The auxiliary contactor 218 mayadditionally be controllable manually, and/or other auxiliary contactor218 may be in-line for the auxiliary power that are controllablemanually Δn example auxiliary contactor 218 includes a solenoid (orother coil-based) contactor, such that energizing the solenoid providesfor either connected auxiliary power (e.g., normally open, or power isdisconnected when not energized) and/or energizing the solenoid providesfor disconnected auxiliary power (e.g., normally closed, or power isconnected when not energized). The characteristics of the system 100,including design choices about whether power should be active whencontroller 214 power fails, servicing plans, regulations and/or policiesin place, the consequences of power loss for the system 100, the voltagetypically carried on the auxiliary power source(s), the availability ofa positive manual disconnect option, and the like, may inform or dictatethe decision of whether the auxiliary contactor 218 is normally open ornormally closed. In certain embodiments, the auxiliary contactor 218 maybe a solid state device such as a solid state relay. The auxiliarycontactor 218 may be additionally controllable by devices outside thePDU 102—for example a keyswitch lockout, another controller in thesystem 100 having access to control the auxiliary contactor 218, etc.,and/or the controller 214 may be responsive to outside commands to openor close the auxiliary contactor 218, and/or additional contactorsin-line for the auxiliary power may be responsive to devices outside thePDU 102. In certain embodiments, auxiliary contactors 218 may beprovided for each auxiliary line, for subsets of the auxiliary lines(e.g., four auxiliary power inputs, with 2, 3, or 4 auxiliary contactors218), etc.

An example PDU 102 includes a current source 220, which may be analternating current source, and/or which may be provided as solid stateelectronics on the controller 214. The current source 220 is capable ofproviding a selected current injection to the main power across a mainfuse 222, for example as AC current, DC current, and/or controllablecurrent over time. For example, the PDU 102 may include sensors such asvoltage and/or current sensors on the main power, and the current source220 provides an electrical connection to a power source (which may be anexternal power source and/or sourced through the controller) in a mannerconfigured to inject the desired current to the main power. The currentsource 220 may include feedback to ensure the desired current isinjected, for example to respond to system noise, variability, andaging, and/or may apply the nominal electrical connection to injectcurrent, and the controller 214 determines sensor inputs to determinewhat current was actually injected on the main power. The example PDU102 depicts a current source 220 associated with the main fuse 222, butthe PDU 102 may further include one or more current sources 220associated with any one or more of the fuses 222, 224 in the PDU 102,including across fuses individually, in subsets, or across all of thefuses (subject to compatibility of power on the fuses—for examplesimultaneous current injection across electrically coupled fuses shouldgenerally be avoided) at once. It can be seen that the inclusion ofadditional current sources 220 provides for greater resolution ininjecting current across individual fuses and in managing variation ofthe fuses over time, which the inclusion of fewer current sources 220reduces system cost and complexity. In certain embodiments the currentsource 220 is configured to selectively inject current across each fusein the PDU 102, and/or across each fuse of interest, in a sequence orschedule, and/or as requested by a controller 214.

The example PDU 102 includes the main fuse 222 and the auxiliary fuses224. The main fuse 222 or fuses are associated with the main power, andthe auxiliary fuses 224 are associated with the auxiliary power. Incertain embodiments, the fuses are thermal fuses, such as resistivedevices that exhibit heating, and are intended to fail if a givencurrent profile is exceeded in the associated power line. ReferencingFIG. 3, a typical and non-limiting example response curve for a fuse isdepicted. The curve 302 represents an application damage curve,depicting a current-time space over which some aspect of the applicationwill be damaged if the curve is exceeded. For example, in the exampleapplication damage curve 302, if 10 x rated current is exceeded forabout 50 milliseconds, damage to some aspect of the application willoccur. It will be understood that an application may contain manycomponents, and that the components may differ in the application damagecurve 302. Additionally, each fuse 222, 224 may be associated withdistinct components having a different damage curve than othercomponents. The curve 304 represents a control space, wherein in certainembodiments, the controller 114 provides control protection to keep thesystem from reaching the application damage curve 302 in the event of afuse failure or off-nominal operation. The application damage curve 302may be a specified value, for example a system requirement to be met,where exceedance of the application damage curve 302 does not meet thesystem requirement, although actual damage to components may beexperienced at some other value in the current-time space. The curve 306represents the fuse melting line for an illustrative fuse. At theposition of the fuse melting line 306, the fuse temperature exceeds thefuse design temperature, and the fuse melts. However, the fuse continuesconducting for a period of time after melting commences, as depicted bythe fuse conduction line 308 (e.g., due to conduction through the meltedmaterial before the connection is broken, arcing, and the like). Whenthe time-current space reaches the fuse conduction line 308, the fuse isno longer conducting on the power line, and the line is disconnected. Itwill be understood that specific system dynamics, fuse-to-fusevariability, fuse aging (e.g., induced mechanical or thermaldegradation, changes in composition or oxidation, and the like), theexact nature of the current experienced (e.g., the rise time of thecurrent), and other real-world variables will affect the exact timing ofboth fuse melting and fuse disconnection. However, even with a nominalfuse as depicted in FIG. 3, it can be seen that for very high currents,the nominal fuse conduction line 308, and even the fuse melting line306, can cross the application damage curve 302—for example becausecertain dynamics of the fuse disconnection operation are less responsive(in the time domain) or unresponsive to the current applied at very highcurrent values.

The example PDU 102 further includes a conduction layer 226 associatedwith the auxiliary power, and a conduction layer 228 associated with themain power. The conduction layers 226, 228 include the power couplingsof the power lines to the fuses. In certain embodiments, the conductionlayers 226, 228 are just wires or other conductive couplings between thefuses and the power connections to the PDU 102. Additionally oralternatively, conduction layers 226, 228 may include flat or laminatedportions, for example with stamped or formed conductive layers, toprovide power connections within the PDU 102, and/or portions of theconduction layers 226, 228 may include flat or laminated portions.Without limitation to any other disclosures provided herein, theutilization of flat or laminated portions provides for flexibility inthe manufacture of the conduction layers 226, 228, flexibility in theinstallation and/or a reduced installed footprint of the conductionlayers 226, 228, and/or provides for greater contact area between theconduction layers 226, 228 and portions of the PDU 102—for example thefuses, controller, contactors, or other devices within the PDU 102 wherethermal and/or electrical contact between the conduction layers 226, 228and the other devices are desired. The example conduction layers 226,228 are depicted in association with the fuses, but the conductionlayers 226, 228 may additionally or alternatively be associated with thecontroller 214 (e.g., power coupling, communications within or outsidethe PDU 102, coupling to actuators, coupling to sensors, and/or thermalcoupling), contactors 216, 218, and/or any other device within the PDU102.

Referencing FIG. 4, an example system 400 is a mobile application suchas a vehicle. The example system 400 includes the high voltage battery104 electrically coupled to high voltage loads 106 through the PDU 102.In the example system 400, an auxiliary prime mover, such as an internalcombustion engine 402 (with associated conversion electronics, such as agenerator, motor-generator, and/or inverter) is additionally coupled tothe PDU 102. It is understood that the high voltage battery 104 and/orthe auxiliary prime mover 402 may act as a power source or a load duringcertain operating conditions of the system 400, and additionally thehigh voltage loads 106 (e.g., electric motors or motor-generatorscoupled to the wheels) may act as a load or a source during certainoperating conditions. The description of loads 106 and sources 104herein is non-limiting, and references only nominal operation, ordinaryoperation, and/or operational conditions selected for conceptualdescription, even if the described load 106 and/or source 104 often,usually, or always operates in a mode that is not the described name.For example, the high voltage battery 104 may operate as a power sourceduring motive operations where net energy is being taken from thebattery, and/or as a load during charging operations, motive operationswhere the wheels or auxiliary prime mover are charging the battery, etc.

The example system 400 further includes a powertrain controller 404 tocontrol operations of the powertrain, which may be associated withanother component in the system 400, and/or part of another controllerin the system (e.g., a vehicle controller, battery controller, motor ormotor-generator controller, and/or engine controller). The examplesystem 400 further includes a charger 406 coupled to the high voltagebatter 404 through the PDU 102, and low voltage loads (“12V Auto Loads”in the example of FIG. 4) representing auxiliary and accessory loads inthe system 400. One of skill in the art will recognize the system 400 asincluding a serial hybrid powertrain for a vehicle—for example whereauxiliary power (e.g., the internal combustion engine) interacts onlywith the electrical system to re-charge batteries and/or provideadditional real-time electrical power during operations, but does notmechanically interact with the drive wheels. Additionally oralternatively, a system may include a parallel hybrid system, whereauxiliary power can interact mechanically with the drive wheels, and/orinteract with the electrical system (either, or both). Additionally oralternatively, a system may be a fully electric system, where auxiliarypower is not present, and/or where auxiliary power is present but doesnot interact with the high voltage/motive power system (e.g., analternative power unit to drive accessories, refrigeration, or thelike—which power may be communicated through the PDU 102 but separatedfrom the motive power electrical system). In certain embodiments, motivesystems such as vehicles experience highly transient load cycles—forexample during acceleration, deceleration, stop-and-go traffic,emergency operations, and the like—and accordingly management of powerin such system is complex, and certain devices such as fuses can bevulnerable to the highly transient load cycle. Additionally oralternatively, loss of operations for vehicles can result in costs forsystem down-time, loss or untimely delivery of cargo, and/or significantoperational risks due to failures (e.g., stranding the operator and/orvehicle, loss of operations in traffic, loss of operations on amotor-way, etc.). In certain embodiments, other systems that may behybrid electric and/or fully electric are additionally or alternativelysubject to highly variable duty cycles and/or specific vulnerabilitiesto operational interruptions, such as, without limitation, pumpingoperations, process operations for a larger process (e.g., chemical,refining, drilling, etc.), power generation operations, miningoperations, and the like. System failures for these and other operationsmay involve externalities such as losses associated with the processfailure that go beyond the down-time for the specific system, and/ordown-time for such systems can incur a significant cost.

Referencing FIG. 5, an example system is depicted including a PDU 102.The example PDU 102 has a number of auxiliary power connections (e.g.,charging, power steering, vehicle accessories, and a load return forcurrent detection, in the example), and a main motive/traction powerconnection. The example system 500 includes two high voltage contactors,one for each of the battery high side and low side, where in the exampletwo high voltage contactors are controllable by the system control boardbut may be additionally or alternatively manual (e.g., a switchaccessible by an operator). The system control board additionally cancontrol a master disconnect that can disconnect all power through thePDU 102. The system 500 further depicts a power fuse bypass 502,controllable by the system control board, that supports certainoperations of the present disclosure as described throughout. The system500 depicts a power fuse bypass 502, but may additionally oralternatively include an auxiliary bypass for one or more of theauxiliary fuses, any subset of the auxiliary fuses, and/or for all ofthe auxiliary fuses together. The example system 500 includes anoptional coolant supply and return coupling. The battery coupling in thesystem 500 depicts a 230V to 400V battery coupling, but the high voltagecoupling may be any value. The system control board is depicted ascommunicatively coupled to a 12V CAN network, although the communicativecoupling of the system control board to the surrounding application orsystem can be any network understood in the art, multiple networks(e.g., vehicle, engine, powertrain, private, public, OBD, etc.), and/ormay be or may include a wireless network connection.

Referencing FIG. 6, an illustrative apparatus 1300 is depicted, whichmay include all or portions of a PDU 102. Any descriptions referencinginteractions between the main fuse 222 and laminated layers 226/228herein additionally or alternatively contemplate interactions betweenany fuses and/or connectors in the apparatus 1300, and/or any othercomponent of a PDU 102 as described throughout the present disclosure.The example apparatus 1300 includes contactors 216/218 which may be highvoltage contactors, and/or may be associated with various ones of thefuses 222, 224 in the apparatus 1300. The apparatus 1300 includeslaminated layers 226/228, which may include conductive layers forcertain aspects of the conductive circuitry in the apparatus 1300. Thelaminated layers 226/228 may additionally or alternatively providestiffness and/or structural support for various components in theapparatus 1300. The laminated layers 226/228 may be configured tointeract with any components in a manner desired to support thefunctions of the laminated layers 226/228, including structuralfunctions, heat transfer functions, and/or electrical conductivityfunctions. The example laminated layers 226/228 interact with allcontactors and fuses in the apparatus 1300, although laminated layers226/228 can readily be configured to interact with selected ones of thecontactors and/or fuses, and/or with other components in the apparatus,for example in a manner similar to a printed circuit board (PCB) design.The example apparatus 1300 is positioned on a L-bracket, which may be afinal configuration, and/or may be a test configuration. In certainembodiments, the apparatus 1300 is enclosed in a dedicated housing,and/or enclosed in a housing of another device in a system 100—such asthe battery housing. In certain embodiments, the apparatus 1300 includesa removable housing portion (e.g., a top portion, lid, etc.) for serviceand/or maintenance access to the components of the apparatus. Theexample apparatus 1300 includes connectors 1302—for example to providepower, datalink access, connections to the power source 104, connectionsto loads 106, connections to sensors (not shown), and/or any other typeof connection to the system 100 or otherwise.

Referencing FIG. 7, an alternate view of an apparatus 1300 is depicted.The apparatus 1300 depicted in FIG. 7 shows the physical interactionbetween the main fuse 222 and the laminated layers 226/228 for anexample embodiment. Referencing FIG. 8, a closer detail view ofinteractions between the main fuse 222 and the laminated layers 226/228is depicted for an example embodiment. In the example of FIG. 8, it canbe seen that the main fuse 222 includes a relatively large thermalcontact area with the laminated layers 226/228 on a bottom side of thefuse, and a relatively small thermal contact area with the laminatedlayers 226/228 on the mounting sides (e.g., through the mountingcomponents). The thermal contact area between the main fuse 222 and thelaminated layers 226/228 is selectable, and in certain embodiments themounting side or an open side of the main fuse 222 includes a greaterthermal contact area, and/or the bottom side includes a large thermalcontact area or is not in significant thermal contact with the laminatedlayers 226/228.

Referencing FIG. 9, a detail view of a side section of the laminatedlayers 226/228 is depicted. The laminated layers 226/228 in the exampleinclude an outer structural layer 1402 and an opposing outer structurallayer (not numbered), with an interstitial space 1404 between the outerstructural layers. In certain embodiments, conductive flow paths and/orthermal flow paths are provided in the interstitial space 1404 betweenthe structural layers. It will be understood that the use of two outerstructural layers 1402 provides certain mechanical advantages, includingincreased durability to shocks and minor impacts, denting of a layer,and bending or flexing of the PDU 102. Additionally or alternatively,the use of two outer structural layers 1402 provides for improvedmechanical moments for certain types of stresses. Accordingly, incertain embodiments, the interstitial space 1404 is empty (e.g., itforms a gap), and/or negligible (e.g., the outer layers are sandwicheddirectly together at least in certain portions of the PDU 102), andnevertheless an improved design is achieved. In certain embodiments, theinterstitial space 1404 includes thermally conductive members (e.g.,high thermal conductivity paths at selected locations), electricallyconductive members (e.g., high electrical conductivity paths at selectedlocations), active and/or convective thermal paths (e.g., coolant orother convective thermal materials that flow through selected paths inthe interstitial space 1404), insulating materials (e.g., to directelectrical or heat flow, and/or to separate components or layerselectrically and/or thermally), and/or dielectric materials (e.g., toimprove electric isolation of components and/or layers).

Referencing FIG. 10, a top view of an example apparatus 1300 isdepicted. The laminated layers 226/228 are distributed throughout theapparatus 1300, providing selectable support, thermal conductivitypaths, and/or electrical conductivity paths, to any desired componentsin the apparatus. Referencing FIG. 11, a side detail view of theinteractive space 1408 between the laminated layers 226/228 and the mainfuse 222 is depicted. The interactive space includes thermallyconductive paths between mount points on the main fuse 222 and thelaminated layers 226/228. Additionally, the interstitial space 1404between the layers is present, in the example, along both the bottom andside of the main fuse 222. Accordingly, desired thermal transfer and/orelectrical communication between the main fuse 222 and the interstitiallayer 226/228 (and thereby with any other selected components in theapparatus 1300) is available as desired. In certain embodiments, greaterthermal and/or electrical coupling between the main fuse 222 and thelaminated layers 226/228 is provided—for example by running thelaminated layers 226/228 along the housing of the main fuse 222 ratherthan offset from the housing, and/or by providing a thermally conductiveconnection (e.g., thermal grease, silicone, and/or contact utilizing anyother thermally coupling material such as a metal or other conductor)between the main fuse 222 and the laminated layers 226/228.

Referencing FIG. 12, a main fuse 222 coupled to laminated layers 226/228on a bottom side of the main fuse 222 is depicted. The example of FIG.12 depicts a thermally conductive layer 1406 disposed between the mainfuse 222 and the laminated layers 226/228—for example thermal grease,silicone, a silicone pad, a mounted metal material, and/or any otherthermally conductive layer understood in the art. In the example of FIG.12, the increased effective thermal contact area provides for greaterheat transfer away from the main fuse 222 when the main fuse 222 getshotter than the laminated layer 226, 228. Additionally, the heat can bedirected away by the inclusion of a thermally conductive material withinthe interstitial space 1404 (e.g., reference FIG. 14), including forexample utilizing a conductive path the direct heat to a selectedportion of a PDU housing, to an active cooling exchange, heating fins,or the like. In the example of FIG. 12, the support layers 226/228 thatthe fuse 222 is coupled to in FIG. 12 may additionally or alternativelyinclude be only a single layer (e.g., not a laminated layer, and/orlayers 226, 228 having no interstitial space 1404), a housing of the PDU102, and/or another component in a system 100 such as a battery packhousing. In certain embodiments, the heat conductivity in FIG. 12 isenhanced by the laminated layers 226/228, for example by the inclusionof a highly conductive channel in the interstitial space 1404, which maybe improved by the structural support, routing availability, and/orenvironmental isolation provided by the laminated layers 226/228.Referencing FIG. 13, in addition to the features depicted in FIG. 12,fins 1502 for improved heat transfer and/or structural rigidity aredepicted upon the laminated layers 226/228 (which may be laminatedlayers, a single layer, a housing wall, etc.). In certain embodiments,the fins are oriented such that fluid flows past them in a direction toenhance heat transfer (e.g., oriented for improved effective flow areaand/or turbulence generation in a liquid flow, to maximize effectivearea in a gas flow, and/or to allow natural convection of fluid—such asgas rising—to cause a high effective flow area of the fins 1502). Incertain embodiments, for example where the support layers 226, 228(and/or layer 226) is a portion of a housing, battery pack housing, orother device, the fins 1502 may instead be presented into ambient air, aforced air flow region, or in a region to be in contact with anyselected fluid to facilitate heat transfer to the fluid.

Convective heat transfer, as utilized herein, includes any heat transferpath wherein convective heat transfer forms at least a portion of theoverall heat transfer mechanism. For example, where a portion of theheat transfer is conductive (e.g., through a wall, thermal grease, etc.)into a flowing fluid (where generally convective heat transferdominates), then the heat transfer mechanism is convective and/orincludes a convective portion. In certain embodiments, heat transferutilizing an active or passively flowing fluid include convective heattransfer as utilized herein. The heat transfer may be dominated byconduction under certain operating conditions, dominated by convectionunder certain operating conditions, and/or include contributing mixes ofconductive and convective heat transfer under certain operatingconditions.

Referencing FIG. 14, in addition to the features depicted in FIG. 12, afluid flow 1602 through the interstitial space 1404 is provided, whichin certain embodiments enhances the heat flow from the main fuse 222 tothe laminated layers 226/228. The fluid flow 1602 may be a coolant(e.g., a vehicle, engine, battery pack, and/or transmission coolant, orother coolant source available in the system), and/or may be a dedicatedcoolant such as a closed system for the PDU 102 and/or power source 104.In certain embodiments, the fluid flow 1602 includes a gas (e.g., air,compressed air, etc.). In certain embodiments, coolant flow may beactive (e.g., through a valve from a pressurized source, and/or pumped)or passive (e.g., configured to occur during normal operations withoutfurther control or input).

Referencing FIG. 15, a main fuse 222 is depicted having enhanced thermalconnectivity to laminated layers 226, 228 (which may be laminated, asingle layer, a housing, etc.). In the example, enhanced thermalconductivity is provided by a thermal coupling layer 1406, but mayalternatively or additionally include positioning the layers 226, 228 inproximity to the main fuse 222, and/or providing another highconductivity path (e.g., a metal, etc.) to a selected location of thelayer 226, 228 and/or the thermal coupling layer 1406. The embodiment ofFIG. 15 provides additional heat transfer capability for the main fuse222, similar to that depicted in FIG. 12, and the embodiments of FIGS.12, 13, 14, and 15 may be fully or partially combined.

Referencing FIG. 16, a high conductivity thermal path 1702 to move heatout of the laminated layers 226/228 is depicted. The high conductivitythermal path 1702 may be combined with any other embodiments describedthroughout the present disclosure to control heat flow in a desiredmanner. In certain embodiments, the high conductivity thermal path 1702is thermally coupled 1706 to another portion of the laminated layers226, 228, to a housing, to a single layer, or to any other desiredcomponent in the PDU 102 or within thermal connectivity of the PDU 102.The portion of FIG. 16 receiving the transferred heat may additionallyor alternatively be coupled to active or passive heat transfercomponents, include fins or other heat transfer enhancement aspects,and/or may be thermally coupled to a convective heat transfer componentor fluid.

Referencing FIG. 17, the fluid flow 1602 is displaced from the portionof the laminated layers 226/228 in direct thermal contact to the mainfuse 222. The example includes the fluid flow 1602 below the main fuse222, and the main fuse 222 thermally coupled to the laminated layers226/228 on the sides of the fuse, but the fluid flow 1602 may be oneither side or both sides of the main fuse 222, with the main fuse 222thermally coupled to another one of the sides and/or the bottom of themain fuse 222, and combinations of any of the foregoing. Thedescriptions of FIGS. 12 through 17 are described in the context of themain fuse 222, but the embodiments therein may apply to any one or moreselected components of the PDU 102, including without limitation anyfuse, connector, and/or controller positioned within the PDU 102.

Referencing FIG. 18, an example system includes the PDU 102 positionedwithin a battery pack housing or enclosure, where the battery cells(e.g., power source 104) are thermally coupled to a heating/coolingsystem 1802 present in the system. Additionally or alternatively, thePDU 102 may be thermally coupled to the battery cells 104, for examplewith conductive paths, at a housing interface, or the like, and/or thePDU 102 may be thermally isolated from the battery cells 104 and/or onlyin nominal thermal connectivity with the battery cells 104 (e.g., anarrangement where some heat transfer therebetween is expected, butwithout intentional design elements to increase the heat transferbetween the PDU 102 and the battery cells 104). Referencing FIG. 19, anexample system includes the PDU 102 in the coolant loop for the heattransfer system 1802, for example with thermal coupling aspects providedto transfer heat from the PDU 102 to the coolant loop and/or with thecoolant loop including a flow branch in thermal contact with the PDU102. The example in FIG. 19 depicts a series coolant arrangement betweenthe battery cells 104 and the PDU 102, but any arrangement iscontemplated herein including at least a parallel arrangement, a seriesarrangement with the PDU 102 contacted first, and/or mixed arrangements(e.g., portions of one of the battery cells 104 and the PDU 102contacted, then all or a portion of the other, etc.).

An example procedure includes an operation to provide active and/orpassive cooling to a temperature sensitive component on a PDU 102. Theexample procedure further includes cooling the temperature sensitivecomponent sufficiently to extend a life of the component to a designedservice life, to a predetermined maintenance interval, to a life and/orpredetermined maintenance interval of the PDU 102 and/or a battery pack,and/or to reduce a temperature of a fuse to avoid thermal/mechanicaldamage to the fuse, a “nuisance fault” of the fuse (e.g., a failure ofthe fuse not occurring due to a designed protective mechanism of thefuse, such as over-current operation).

In certain embodiments, fuse design imposes complications on system—forexample a fuse threshold may be desired for the fuse to engage betweenabout 135% up to 300% of the system overcurrent threshold value.However, a fuse on the smaller end of the scale may fail due to thermaland/or mechanical fatigue over the life of the system, causing a“nuisance failure” or a fuse failure that is not due to the protectivefunction of the fuse. Such failures cause high costs, down-time,degraded perception of the product embodying the system, potentiallydangerous situations or stranding due to power loss, and the like.Designing a larger fuse to avoid nuisance failures can impose theexternal system to increased risk of an overcurrent event, and/orsignificant costs to upgrade the rest of the power system. Additionally,design of a system for multiple maximum power availabilities (e.g., onepower system for two different power ratings) requires that the fuseplan be altered or designed to accommodate multiple systems. In certainembodiments, the same hardware may be utilized for different powerratings, and/or changed after the system is in operation, providing foran off-nominal fuse sizing for at least one of the multiple powerratings.

Referencing FIG. 20, an example apparatus 1900 for providing additionalprotection against fuse nuisance faults and system failures isdescribed. The example apparatus 1900, for example implemented on thecontroller 214, includes a current event determination circuit 1902 thatdetermines a current event 1904 is active or predicted to occur, wherethe current event includes a component experiencing (or about toexperience) a wear event—such as a current value that will cause thermaland/or mechanical stress on the component but may not cause an immediatefailure or observable damage. An example component includes the fuse,but may be any other component in the system including a battery cell, aswitch or connector, a motor, etc. Another example current eventincludes a system failure value—for example a current value that willpossibly or is expected to cause a system failure (e.g., a cablefailure, connector failure, etc.).

The apparatus 1900 further includes a response determination circuit1906 that determines a system response value 1910 to the current event1904. Example and non-limiting responses include notifying an operatorto reduce power, reducing power, notifying a system controller that acurrent event 1904 is present or imminent, opening a contactor on thecircuit related to the event, delaying circuit protection, monitoringthe event and a cause for response delay and responding at a later time,and/or scheduling a response according to an operating condition in thesystem. The apparatus 1900 further includes a response implementationcircuit 1908, where the response implementation circuit 1908 determinescommunications and/or actuator responses according to the systemresponse value 1910, and provides network communications 1912 and/oractuator commands 1914 to implement the system response value 1910.Example and non-limiting actuator responses include operating acontactor, operating an active coolant actuator to modulate thermalconduction away from the fuse, or the like.

Referencing FIG. 21, illustrative data 2000 for implementing a systemresponse value 1910 is depicted. The illustrative data 2000 includes athreshold value 2002—for example a current, temperature, indexparameter, or other value at which component wear and/or system failureis expected to occur, and utilized as a threshold by the current eventdetermination circuit 1902—at least under certain operating conditionsat a point in time for the system. It is understood that the currentevent determination circuit 1902 may utilize multiple thresholds, and/ordynamic thresholds, as described throughout the present disclosure. Thecurve 2004 represents the nominal system performance, for example thecurrent, temperature, index parameter, or the like that will beexperienced by the system in the absence of operations of the apparatus1900. In the example, the response determination circuit 1906 determinesthat the threshold value 2002 will be crossed, and accounts for acontactor disconnection time 2008 (and/or an active coolant loopresponse time), commanding the contactor and/or increasing thermalconduction away from the fuse, in time to avoid crossing the thresholdvalue 2002. The illustrative data 2000 depicts a resulting systemresponse curve 2006, wherein the resulting system performance is keptbelow the threshold value 2002. The system may experience alternativeresponse trajectories (e.g., the resulting system response curve 2006may fall well below the threshold value 2002 depending upon the dynamicsof the system, how long the contactor is kept open, etc.). Additionallyor alternatively, the response determination circuit 1906 maynevertheless allow the threshold value 2002 to be crossed, for exampleaccording to any operations or determinations described throughout thepresent disclosure. In certain embodiments, the response determinationcircuit 1906 allows the threshold value 2002 to be crossed, but resultsin a lower peak value of the response, and/or a lower area under theresponse curve that is above the threshold value 2002, than would occurwithout the operations of the response determination circuit 1906.

An example procedure, which may be performed by an apparatus such asapparatus 1900, includes an operation to determine that a current event(or other response event) is exceeding or predicted to exceed a wearthreshold value, and/or determining that the current event is exceedingor predicted to exceed a system failure value. In response todetermining the current event is exceeding or predicted to exceed eithervalue, the procedure includes an operation to perform a mitigatingaction. The component for the wear threshold value may be a fuse (e.g.,the fuse is experiencing or expected to experience a current event thatwill cause mechanical stress, thermal stress, or high usage of the fuselife), a component in the system (e.g., a contactor, a cable, a switch,a battery cell, etc.), and/or a defined threshold value that isnominally determined (e.g., calibration for a value that is expected tobe relevant to possible component damage, without being necessarily tiedto a specific component). In certain embodiments, the wear thresholdvalue and/or the system failure value are compensated for the age orwear state of the system or a component in the system (e.g., thresholdsare reduced, and/or responses are increased, as the system ages).

Non-limiting mitigating actions, which may be system response values1910, include, without limitation: 1) disconnecting a circuit having thewear component (e.g., the fuse, system component, and/or the specificpower line experiencing the event); 2) notifying an operator to reduce apower request; 3) notifying a vehicle or powertrain controller of thecurrent event; 4) adjusting or limiting available power to the operator;5) delaying circuit protection (disconnection and/or power reduction) inresponse to circumstances (e.g., in traffic, moving vehicle, applicationtype, notification from an operator that continued operation isrequired, etc.)—including allowing a component in the system toexperience the underlying wear event and/or failure event; 6) continuedmonitoring and disconnecting the circuit (or reducing power, etc.) ifthe event persists and if later conditions allow; 7) scheduling theresponse according to an operating mode of the system (e.g., sport,economy, emergency, fleet operator (and/or policy), owner/operator(and/or policy), geographic policy, and/or regulatory policy); and/or 8)bypassing the wear component (e.g., bypassing current around a fuse as aresponse action).

In certain embodiments, the operation to determine that the currentevent is exceeding the wear threshold value and/or the system failurevalue is based upon a calculation such as: 1) determining the currentthrough the circuit exceeds a threshold value (e.g., an amp value); 2)determining a rate of change of the current through the circuit exceedsa threshold value (e.g., an amp/second value); and/or 3) determiningthat an index parameter exceeds a threshold value (e.g., the indexincluding accumulated amp-seconds; amp/sec-seconds; a counting index forperiods above a threshold value or more than one threshold value; acounting index weighted by the instantaneous current value; anintegrated current, heat transfer, and/or power value; and/or countingdown or resetting these based on current operating conditions).

In certain embodiments, the operation to determine that the currentevent is exceeding the wear threshold value and/or the system failurevalue includes or is adjusted based upon one or more of: 1) a trip curve(e.g., a power-time or current-time trajectory, and/or an operatingcurve on a data set or table such as that represented in FIG. 3); 2) afuse temperature model, including a first or second derivative of thetemperature, and one or more temperature thresholds for scheduled and/orescalating response; 3) a measured battery voltage (e.g., current valuesmay be higher as battery voltage lowers, and/or dynamic response ofcurrent may change causing changes for the wear threshold value, systemfailure value, and/or current event determination); 4) a firstderivative of current, temperature, power demand, and/or an indexparameter; 5) a second derivative of current, temperature, power demand,and/or an index parameter; 6) information from a battery managementsystem (e.g., voltage, current, state of charge, state of health, rateof change of any of these, which parameters may affect current values,expected current values, and/or dynamic response of current values,causing changes for the wear threshold value, system failure value,and/or current event determination); 7) determination of and monitoringof contactor disconnect times, and accounting for the contactordisconnect time in determining the response to the current event; 8)utilizing ancillary system information and adjusting the response (e.g.,a power request from operations that is expected to create an upcomingchange, a supplemental restraint system active/deploying—open contactors(cut power); collision avoidance system active—keep contactors closedfor maximum system control; and/or an anti-lock brake system and/ortraction control system active—keep contactors closed for maximum systemcontrol). In certain embodiments, a degree of activation may also beconsidered, and/or system status may be communicated to the PDU—forexample the system may report critical operation requiring power as longas possible, or shut-down operations requiring power to be cut as soonas possible, etc.

Referencing FIG. 22, an example apparatus 600 to measure current througha fuse utilizing active current injection is schematically depicted. Theapparatus 600 includes the controller 214 having a number of circuitsconfigured to functionally execute operations of the controller 214. Thecontroller 214 includes an injection control circuit 602 that providesan injection command 604, where the current source 220 is responsive tothe injection command 604. The controller 214 further includes aninjection configuration circuit 606 that selects a frequency, amplitude,and/or waveform characteristic (injection characteristic 608) for theinjection command 604. The controller 214 further includes a duty cycledescription circuit 610 that determines a duty cycle 612 for a systemincluding the controller 214, where the duty cycle includes adescription of currents and voltages experienced by the fuse. In certainembodiments, the duty cycle description circuit 612 further updates theduty cycle 612, for example by observing the duty cycle over time, overa number of trips, over a number of operating hours, and/or over anumber of miles traveled. In certain embodiments, the duty cycledescription circuit 612 provides the duty cycle as an aggregated dutycycle, such as a filtered duty cycle, averaged duty cycle, weightedaverage duty cycle, bucketed duty cycle with a quantitative descriptionof a number of operating regions, or the like, and selects or mixes acalibration from a number of calibrations 614, each calibrationcorresponding to a defined duty cycle.

An example procedure to determine fuse current throughput is describedfollowing. In certain embodiments, one or more aspects of the proceduremay be performed by an apparatus 600. The procedure includes anoperation to inject a current having a selected frequency, amplitude,and/or waveform characteristic into the circuit through the fuse, and toestimate the fuse resistance (including dynamic resistance and/orimpedance) in response to the measured injected AC voltages and theinjected current. In certain embodiments, the selected frequency,amplitude, and/or waveform characteristic is selected to provide for anacceptable, improved, or optimized measurement of the fuse resistance.For example, the base power current through the fuse to supportoperations of the application have a certain amplitude and frequencycharacteristic (where frequency includes both the power frequency if AC,and the long term variability of the amplitude if AC or DC). Theinjected current may have a selected frequency and/or amplitude to allowfor acceptable detection of the fuse resistance in view of the basepower current characteristics, and also selected to avoid interferencewith the operations of the application. For example, if the base powercurrent is high, a higher amplitude of the injection current may beindicated, both to support measurement of the injected AC voltage, andbecause the base power current will allow for a higher injected currentwithout interfering with the operations of the system. In anotherexample, a frequency may be selected that is faster than currentvariability due to operations, that does not impinge upon a resonantfrequency or harmonic frequency of a component in the system, or thelike.

An example procedure includes storing a number of calibration valuescorresponding to various duty cycles of the system (e.g.,current-voltage trajectories experienced by the system, bucketed timewindows of current-voltage values, etc.), determining the duty cycle ofthe system, and selecting a calibration value from the calibrationvalues in response to the determined duty cycle. The calibration valuescorrespond to the current injection settings for the current injectionsource, and/or to filter values for digital filters to measure the fusevoltage and/or fuse current values. In certain embodiments, the dutycycle can be tracked during operations, and updated in real-time or atshutdown. In certain embodiments, an aggregated duty cycle descriptionis stored, which is updated by data as observed. An example aggregatedduty cycle includes a moving average of the duty cycle observed (e.g., aduty cycle defined as a trip, power on to power off cycle, operatingtime period, and/or distance traveled), a filtered average of the dutycycle (e.g., with selected filter constants to provide the desiredresponse to a change—for example to respond within one trip, five trips,30 trips, one day, one week, one month, etc.). In certain embodiments,the duty cycle updates occur with a weighted average (e.g., longertrips, higher confidence determinations, and/or operator selections orinputs may be weighted more heavily in determining the duty cycle).

A response indicates the period until the system is acting substantiallybased upon the changed duty cycle information, for example wherecalibration A is for a first duty cycle and calibration B is for thechanged duty cycle, the system may be deemed to have responded to thechange when 60% of calibration B is utilized, 90% of calibration B isutilized, 96% of calibration B is utilized, and/or when the system hasswitched over to calibration B. The utilization of multiple calibrationsmay be continuous or discrete, and certain aspects of the calibrationsindividually may be continuous or discrete. For example, wherecalibration A is selected, a particular amplitude (or trajectory ofamplitudes), frequency (or trajectory of frequencies), and/or waveform(or number of waveforms) may be utilized, and where calibration B isselected, a different set of amplitudes, frequencies, and/or waveformsmay be utilized. Where a duty cycle is positioned between A and B,and/or where the duty cycle response is moving between A and B, thesystem can utilize mixtures of the A and B duty cycles, and/or switchbetween the A and B duty cycles. In a further example, the switchingbetween the A and B duty cycles can occur in a mixed fashion—for examplewhere the current response is at 80% of B, then calibration B may beutilized 80% of the time and calibration A may be utilized 20% of thetime. In certain embodiments, the calibration may be switched abruptlyat a certain threshold (e.g., at 70% response toward the newcalibration), which may include hysteresis (e.g., switch to calibrationB at 80% of the distance between calibration A and B, but switch backonly when at 40% of the distance between calibration A and B). Incertain embodiments, certain aspects (e.g., the amplitude) may movecontinuously between calibrations, where other aspects (e.g., thewaveform) utilize only one calibration or the other. In certainembodiments, indicators of quality feedback may be utilized to adjustthe calibration response (e.g., where, during movement towardcalibration B, the indicated fuse resistance appears to be determinedwith greater certainty, the system moves the response toward calibrationB more quickly than otherwise, which may include utilizing more ofcalibration B than indicated by the current aggregated duty cycle,and/or adjusting the aggregated duty cycle to reflect a greaterconfidence that the duty cycle is going to be maintained).

Example amplitude selections include both the peak amplitude of theinjected current, the adjustment from the baseline (e.g., higherincrease than decrease, or the reverse), and/or the shape of amplitudegeneration (e.g., which may be in addition to or incorporated within thewaveform selection). Additionally or alternatively, the amplitude for agiven calibration may be adjusted throughout a particular currentinjection event—for example to provide observations at a number ofamplitudes within the current injection event. Example frequencyselections include adjusting the frequency of the periods of the currentinjection events, and may further include testing at a number ofdiscrete frequencies, sweeping the frequencies through one or moreselected ranges, and combinations of these. Example waveform selectionsinclude waveform selections to induce desired responses, to be morerobust to system noise (e.g., variability in the base current,inductance and/or capacitance of components in the system, or the like),to enhance the ability of the current injection detection to isolate theinjected current from the load current, and/or may include utilizationof multiple waveforms in a given calibration to provide a number ofdifferent tests. In certain embodiments, where multiple amplitudes,frequencies, and/or waveforms are utilized, the injected AC voltage (andcorresponding fuse resistance) can be determined by averaging measuredparameters, by using higher confidence measurements, and/or byeliminating outlying measurements from the injected AC voltagedetermination.

According to the present description, operations to provide a highconfidence determination of a fuse resistance value in a PDU 102 aredescribed. In certain embodiments, the high confidence determination ofthe fuse resistance can be utilized to determine the fuse condition, toprovide a high accuracy or high precision determination of currentthrough the fuse and of power consumption by the system 100, and/or toperform system diagnostics, fault management, circuit management, or thelike.

Referencing FIG. 23, an example apparatus 700 to determine a null offsetvoltage and/or diagnose a system component are schematically depicted.The example apparatus 700 includes a controller 214 having a fuse loadcircuit 702 that determines that no current is demanded for a fuse load704. The example apparatus 700 further includes a null offset voltagedetermination circuit 706 that determines a null offset voltage 708 inresponse to the fuse load 704 indicating that no current is demanded.The example apparatus 700 further includes a component diagnosticcircuit 710 that determines whether a component is degraded, failed,and/or in a fault or off-nominal condition in response to the nulloffset voltage 708, and determines fault information 716 in response tothe determining whether a component is degraded, failed, and/or in afault or off-nominal condition (e.g., fault counters, fault values,and/or component-specific information). Operations of the componentdiagnostic circuit 710 include comparing the null offset nominal voltage708 to a null offset voltage threshold value 712, and/or performingoperations to determine which component is causing an off-nominal nulloffset voltage 708. The example apparatus 700 further includes a nulloffset data management circuit 714 that stores the null offset voltage708, and/or any diagnostic or fault information 706 such as faultcounters, fault values, and/or indications of which component is causingthe off-nominal null offset voltage 708. In certain embodiments, wherecontributions to the null offset voltage 708 are determined separatelyfor certain components, an example null offset data management circuit714 stores individual contributions of the null offset voltage 708separately. In certain embodiments, the utilization of the null offsetvoltage 708 improves the accuracy of determining the fuse resistancefrom the injected current.

An example procedure to determine null offset voltage for a fuse currentmeasurement system is described following. The example procedure may beperformed by a system component such as an apparatus 700. Null offsetvoltages occur in a controller 214 due to individual offsets of op-ampsand other solid state components in the controller 214, as well as dueto part-to-part variations, temperature drift, and degradation of one ormore components in the system over time. The presence of a null offsetvoltage limits the accuracy with which current measurement through afuse is available, and can thereby limit the types of controls anddiagnostics that can be performed in the system.

An example procedure includes an operation to determine that no currentis demanded for a fuse load. Example operations to determine that nocurrent is demanded for a fuse load include a recent key-on or key-offevent for a vehicle (e.g., the vehicle is starting, powering down, is inan accessory position, and/or has not yet engaged power to the fuse ofinterest), observation of the fuse circuit, and/or by a statusobservation provided by another controller in the system (e.g., apowertrain controller is explicitly indicating that no power is beingprovided, is indicating a status inconsistent with power being provided,etc.). An example operation determines that no current is demanded for afuse during a key-off event, and/or within a time period after a key-onevent.

The example procedure further includes an operation to determine thenull offset voltage in response to determining that no current isdemanded for the fuse load, and an operation to store the null offsetvoltage. In certain embodiments, the stored null offset voltage isstored in non-volatile memory, for example to be utilized in asubsequent operation of the system. In certain embodiments, the nulloffset voltage is stored in a volatile memory and utilized for a currentoperation cycle. The stored null offset voltage may be replaced when anew value is determined for the null offset voltage, and/or updated in ascheduled manner (e.g., by averaging in or filtering in updated values,by holding new values for subsequent confirmation before being applied,etc.).

An example procedure further includes diagnosing a component of thesystem in response to the null offset voltage. For example, as the nulloffset voltage increases over time, a degradation of the controller 214may be indicated, and a fault (visible or service available) may beprovided to indicate that the controller 214 is operating off-nominallyor failed. Additionally or alternatively, a contactor (e.g., the maincontactor 216) may be diagnosed in response to the null offset voltage.In certain embodiments, further operations such as engaging anothercontactor in-line with the diagnosed contactor may be utilized toconfirm which component of the system is degraded or failed. In certainembodiments, the controller 214 may cut power to one or more componentswithin the controller 214 to confirm that the controller 214 componentsare causing the offset voltage. In certain embodiments, the procedureincludes determining the individual contributions of components to theoffset voltage—for example by separating the controller 214 contributionand the contactor contribution. In response to the offset voltage beingabove a threshold value and/or confirming which component of the systemis causing the off-nominal offset voltage, the controller 214 mayincrement a fault value, set a fault value, and/or set a service ordiagnostic value. In certain embodiments, the null offset voltage and/orany fault values may be made available to the system, to a network,and/or communicated to another controller on the network.

According to the present description, operations to provide a nominaloffset voltage for high confidence determination of a fuse current and afuse resistance value in a PDU 102 are described. In certainembodiments, the high confidence determination of the fuse resistancecan be utilized to determine the fuse condition, to provide a highaccuracy or high precision determination of current through the fuse andof power consumption by the system 100, and/or to perform systemdiagnostics, fault management, circuit management, or the like.

Referencing FIG. 24, an example apparatus 800 to provide for digitalfiltering of a current measurement through a fuse circuit is depictedschematically. In certain embodiments, where current is injected througha fuse, the measurement of the base power current and the injected ACcurrent through the fuse are de-coupled utilizing a low-pass filter(pulling out the base power signal) and a high-pass filter (pulling outthe injected current signal). Previously known systems utilize an analogfilter system—for example constructed of capacitors, resistors, and/orinductive devices, that provide the selected filtering of the signal andthereby provide the separated base power signal and injected currentsignal. However, analog filter systems suffer from a number ofdrawbacks. First, analog systems are not configurable, are onlyconfigurable to a discrete number of pre-considered options, and/or areexpensive to implement. Accordingly, a wide range of base power signalsand injected AC current signals are not typically available for highaccuracy determination of the fuse current with an analog filter system.Additionally, analog filter systems suffer from phase variance betweenthe low-pass filter and the high-pass filter, and/or between thefiltered output and the injected current signal. Accordingly,post-processing and/or acceptance of a less accurate signal arerequired, and accuracy is diminished on the measured current even withpost-processing. Further, if the system has a component that has a basefrequency or harmonic that interferes with the filter, the analog filteris not able to respond and will not provide reliable measurements.Because the frequency dynamics of the system can change over time, forexample as components degrade, are service or replaced, and/or due toenvironmental or duty-cycle driven changes, even careful system designcannot fully resolve the inability of analog filters to respond tointerference from frequency dynamics in the system. The exampleapparatus 800 includes a high-pass digital filter circuit 802 thatdetermines the injected current value 804 for the fuse circuit byproviding a high-pass filter operation on a measured fuse current 814,and a low-pass digital filter circuit 806 that determines the base powercurrent value 808 for the fuse circuit by providing a low-pass filteroperation on the measured fuse current. The example apparatus 800further includes a filter adjustment circuit 812 that interprets a dutycycle 612 and/or an injection characteristic 608, and adjusts thefiltering for the high-pass digital filter circuit 802 and/or theinjection characteristic 608—for example by providing filter adjustments816 such as providing distinct cutoff frequencies to ensure separationof the signals, to raise or lower cutoff frequencies to ensure adescriptive energy portion of the signal is captured, and/or tomanipulate the filters to avoid a frequency or a harmonic in the system.While the example embodiment of FIG. 24 utilizes a digital filter, incertain embodiments the available controller processing resources and/ortime response of digital filtering may lead certain systems to utilizeanalog filters and/or a combination of analog filters with digitalfilters.

An example procedure includes an operation to provide digital filters ina PDU 102 to determine base power and injected current values from ameasured current value through the fuse. The example procedure furtherincludes an operation to determine the base power by performing alow-pass filter operation on the measured current value, and todetermine the injected current value by performing a high-pass filteroperation on the measured current value. The example procedure furtherincludes an operation to adjust parameters of the low-pass filter and/orthe high-pass filter in response to a duty cycle of the system includingthe PDU 102 (including, for example, power, voltage, and/or currentvalues passing through the fuse), and/or in response to an injectioncharacteristic of the injected current through the fuse. The exampleprocedure includes adjusting the parameters to improve the separation ofthe base power and/or injected current values, to improve the accuracyof determining the injected current amount, to adjust to a frequencyand/or a harmonic of a component in the system in electricalcommunication with the fuse, and/or to respond to a system orenvironmental noise affecting one or both of the high-pass and low-passfilters.

According to the present description, operations to implement digitalfilters for de-convoluting a voltage characteristic and currentmeasurement through a fuse are provided. The digital filtering allowsfor the system to provide a high confidence determination of a fusecurrent and a fuse resistance value in a PDU 102. In certainembodiments, the high confidence determination of the fuse resistancecan be utilized to determine the fuse condition, to provide a highaccuracy or high precision determination of current through the fuse andof power consumption by the system 100, and/or to perform systemdiagnostics, fault management, circuit management, or the like.

Fuses for highly transient load applications and/or high duty cyclevariability applications, such as but not limited to electrical systemsfor mobile applications and vehicles experience a number of challenges.Load variation can change considerably throughout operations, includingexperiencing both high positive and high negative current operations,and often in a short period of time (e.g., acceleration and regenerativebraking cycles in stop-and-go traffic; high load operation going up ahill followed by significant regeneration down the other side, etc.).Additionally, current transients and reversals can result in significantinrush currents that are experienced by the fuse. Fuses are designed tofail at a protective current value, which is intended to correspond to afuse temperature value. Because they are designed to fail at arelatively close value to the maximum current demands, they areconsequently one of the most delicate physical parts in the system—bothelectrically and physically. Sub-critical current values and currenttransient values can cause the fuse to suffer thermal and mechanicalstresses, both from temperatures experienced and temperature transients.Fuses subject to significant sub-critical cycling can fail—either bymelting even though the designed failure current has not been exceeded,or by breaking due to mechanical stress. Mobile applications, asdiscussed throughout the present disclosure, are subject to particularlyhigh costs and risks when a mission critical component such as a fusefails (e.g., the vehicle generally does not have motive power availableif a main power fuse fails). Additionally, mobile applications aresubject to high transient loads through the motive power system.

Referencing FIG. 25, an example fuse circuit 2100 is depicted, which maybe present on a PDU 102. The example fuse circuit 2100 may be associatedwith a main fuse, an auxiliary fuse, and/or a group of fuses or a subsetof a group of fuses. The fuse circuit 2100 includes a contactor (C1) inparallel with the fuse (F1). During normal operations the contactor isopen, and the current in the fuse circuit 2100 passes through the fuse.In certain embodiments, the contactor may include physical components(e.g., a solenoid and/or coil-based switch or relay), and/or thecontactor may be a solid state relay. In certain embodiments, thecontactor may be normally-open (e.g., power applied closes thecontactor) or normally-closed (e.g., power applied opens the contactor).The example fuse circuit 2100 allows for the contactor to selectivelybypass the fuse circuit, for example in accordance with operations of anapparatus 1900 (reference FIG. 20 and the corresponding disclosure).

Referencing FIG. 26, another embodiment of a fuse circuit 2200 isdisclosed, with a contactor (C1) in series with a second fuse (F2), andthe C1-F2 branch in parallel with a first fuse F1. The fuse circuit 2200provides for additional flexibility and a number of additional featuresfor operations of an apparatus 1900. For example, normal operation maybe performed with the contactor closed, dividing current between F1 andF2 (in the resistance ratios of the two fuses). An example includes afuse F2 with a low current threshold value, set such that the dividedcurrent would fail fuse F2 if the system design current is exceeded by adesigned amount (e.g., between 135% and 300% of system designcurrent—although any value is contemplated herein). The fuse F1 may beset at a very high value, allowing for the opening of the contactor tobriefly increase the fusing capacity of the circuit but still be fused.Additionally or alternatively, fuse F2 may be a relatively cheap and/oraccessible fuse, and being at a lower current threshold F2 is likely tosuffer greater mechanical and thermal fatigue, and act as the failurepoint for the fuse circuit 2200, which may greatly extend the life ofthe fuse F1 which may be more expensive and/or less accessible.Additionally or alternatively, normal operation may be performed withthe contactor open, with fuse F1 defining the ordinary fusing of thecircuit. When a high transient or other current event occurs, thecontactor is closed, and the branch C1-F2 shares the current load,keeping the fuse F1 within normal or lower wear operating conditions. Incertain embodiments, fuses F1 and F2 may be similarly sized—for exampleto allow fuse F2 to operate as a backup fuse and to keep similar failureconditions in place for F1 and F2. Alternatively, fuse F2 may be smallerthan fuse F1, allowing for alternate operations as described, theintermittent use of the C1-F2 circuit to take up some current to protectfuse F1, and/or to provide back-up fusing for F1—which may be at areduced power limit for the system if the fuse F2 is smaller (e.g., as ade-rated mode of operation, and/or a limp-home mode of operation).Alternatively, fuse F2 may be larger than fuse F1, for example to allowfuse F2 to manage very high transient current conditions where it isdesired that operation still continues. The utilization of a fusecircuit 2200 allows for a high degree of control of the fusing system,to be protective of the power system during nominal operation and stillprovide a high degree of capability during failure modes, foroff-nominal operation, and/or during transient operation. In certainembodiments, a resistor may be provided on the C1-F2 branch, for exampleto control the current sharing load between F1 and F2 when the contactorC1 is closed.

Referencing FIG. 27, a fuse circuit 2300 includes a plurality of fusesF1, F2, F3, F4 depicted in parallel, with a corresponding contactor inseries with each. An example fuse circuit 2300 is for auxiliary fuses,although fuse circuit 2300 can be any fuse, including a main fuse. Theexample fuse circuit 2300 allows for either the removal of fuses fromoperation—for example where one of the fuses is experiencing a transientevent —or for the addition of fuses, such as when a high transient eventoccurs to share the current load. In certain embodiments, one or more ofthe fuses in the fuse circuit 2300 does not have an associatedcontactor, and is a primary load bearing fuse for the fuse circuit 2300.The relative sizing of the fuses in the fuse circuit 2300 may beaccording to any selected values, and will depend upon the purpose ofthe fuse circuit 2300 (e.g., to provide a limp-home feature, to provideadditional capacity, to act as a back-up, and/or to allow for thecut-off of individual fuses in the system). Additionally oralternatively, any one or more of the fuses in fuse circuit 2300 may bepositioned serially with a resistor, for example to control current loadbalancing. In certain embodiments, the fuses F1, F2, F3, F4 are not inparallel, and/or one or more of the fuses is not in parallel.Accordingly, the opening of a contactor for such a fuse will not shuntcurrent to another one of the fuses. An example embodiment includes thecontactors for fuses individually to allow for shutting down of certainsystem capability (e.g., due to a failure, high transient, or the like)without shutting down all system capability (e.g., a fuse supportingbraking may remain active even in a high transient event, while anaccessory fuse for non-critical systems may be cut off to protect thefuse and/or the system).

Referencing FIG. 28, a fuse circuit 2400 is depicted, similar to fusecircuit 2300, except that each fuse has a contactor in parallel,allowing for the shorting of the particular fuse while keeping currentflowing on that fuse's path. In certain embodiments, the parallel pathfor each fuse may include an additional fuse and/or a resistor, suchthat when the fuses are connected in parallel, the load across each fusecircuit remains at least partially balanced. The embodiments of FIGS. 25to 28 may be referenced as current protection circuits, and embodimentssuch as those depicted in FIGS. 25 to 28, and/or as described, allow forselectable configuration of the current protection circuit. Selectableconfiguration of the current protection circuit may include run-timeoperations (e.g., reconfiguring the current protection circuit inresponse to events or operating conditions) and/or design-timeoperations (e.g., allowing a same hardware device to support multiplepower ratings, electrical connection configurations, and/or serviceevent or upgrade changes).

Referencing FIG. 29, illustrative data 2500 showing a fuse response to adrive cycle for a vehicle is depicted. In the example, fuse current(e.g., the dashed line lower curve at times of 12 and 25 units) and fusetemperature (e.g., the solid line upper curve at times of 12 and 25units) are depicted. It will be understood that another parameterdescribing the fuse performance and/or limits may be utilized, includingat least any values described in the portion referencing FIG. 21. Theoperations of the drive cycle exhibit high transients where, in theexample, the fuse temperature is expected to exceed the “fusetemperature avoidance limit”—for example, a temperature or temperaturetransient at which the fuse experiences mechanical stress. An apparatus1900 may consider a number of thresholds for the fuse—for example alight wear threshold, a heavy wear threshold, and a potential failurethreshold, which may be set at distinct values of the fuser performanceindicator being utilized (e.g., temperature). In certain embodiments,more than one type of threshold value may be utilized—for example athreshold or set of thresholds for temperature, a second threshold orset of thresholds for temperature change with time (e.g., dT/dt), etc.In the example, an apparatus 1900 may take mitigating action at thetransient points, for example bypassing the corresponding fuse brieflyto avoid the transient and/or control the rate of transient experiencedby the fuse.

Referencing FIG. 30, an example system 2600 include the power source 104and load 106, with a fuse (F1) electrically disposed between the load106 and the source 104. An operator provides a power request(accelerator pedal input), and an apparatus 1900 determines that theload request will exceed a threshold for the fuse (e.g., according tothe current demand above temperature limit, or some other determination)but may further determine that the transient event will not otherwiseexceed system operating condition limits. In the example, apparatus 1900commands the contactor (C3) to close for a period of time before orduring the transient to protect the fuse. The system 2600 depicts thehigh-side (C1) and low-side (C3) high voltage contactors (e.g., 216, 218from system 100), which are distinct from the fuse bypass contactor C3.

Referencing FIG. 21, illustrative data 2000 for implementing a systemresponse value 1910 is depicted. The illustrative data 2000 includes athreshold value 2002—for example a current, temperature, indexparameter, or other value at which fuse wear and/or failure is expectedto occur, and utilized as a threshold by the current event determinationcircuit 1902—at least under certain operating conditions at a point intime for the system. It is understood that the current eventdetermination circuit 1902 may utilize multiple thresholds, and/ordynamic thresholds, as described throughout the present disclosure. Thecurve 2004 represents the nominal system performance, for example thecurrent, temperature, index parameter, or the like that will beexperienced by the fuse in the absence of operations of the apparatus1900. In the example, the response determination circuit 1906 determinesthat the threshold value 2002 will be crossed, and accounts for acontactor connection/disconnection time 2008 (e.g., to bypass the fuse,engage a second fuse branch, and/or close off a more vulnerable fusebranch), commanding the contactor to connect or disconnect in time toavoid crossing the threshold value 2002. Additionally or alternatively,the response determination circuit 1906 may nevertheless allow thethreshold value 2002 to be crossed, for example according to anyoperations or determinations described throughout the presentdisclosure—for example when a more critical system parameter requiresthe fuse to remain connected, and the fuse is allowed to experience thewear and/or failure event.

In certain embodiments, the operation to determine that the currentevent is exceeding the wear threshold value and/or the fuse failurevalue is based upon a calculation such as: 1) determining the currentthrough the fuse exceeds a threshold value (e.g., an amp value); 2)determining a rate of change of the current through the fuse exceeds athreshold value (e.g., an amp/second value); 3) determining that anindex parameter exceeds a threshold value (e.g., the index includingaccumulated amp-seconds; amp/sec-seconds; a counting index for periodsabove a threshold value or more than one threshold value; a countingindex weighted by the instantaneous current value; an integratedcurrent, heat transfer, and/or power value; and/or counting down orresetting these based on current operating conditions).

In certain embodiments, the operation to determine that the currentevent is exceeding the wear threshold value and/or the fuse failurevalue includes or is adjusted based upon one or more of: 1) a trip curve(e.g., a power-time or current-time trajectory, and/or an operatingcurve on a data set or table such as that represented in FIG. 3); 2) afuse temperature model, including a first or second derivative of thetemperature, and one or more temperature thresholds for scheduled and/orescalating response; 3) a measured battery voltage (e.g., current valuesmay be higher as battery voltage lowers, and/or dynamic response ofcurrent may change causing changes for the wear threshold value, systemfailure value, and/or current event determination); 4) first derivativeof current, temperature, power demand, and/or an index parameter; 5)second derivative of current, temperature, power demand, and/or an indexparameter; 6) information from a battery management system (e.g.,voltage, current, state of charge, state of health, rate of change ofany of these, which parameters may affect current values, expectedcurrent values, and/or dynamic response of current values, causingchanges for the wear threshold value, fuse failure value, and/or currentevent determination); 7) determination of and monitoring of contactorconnection or disconnection times, and accounting for the contactorconnection or disconnection time in determining the response to thecurrent event; 8) utilizing ancillary system information and adjustingthe response (e.g., collision avoidance system active—allow the fuse tofail, and/or bypass the fuse allowing potential damage to the system, tokeep power flowing; anti-lock brake system and/or traction controlsystem active—keep power flowing for maximum system control (degree ofactivation may also be considered, and/or system status communicated tothe PDU—for example the system may report critical operation requiringpower as long as possible, or shut-down operations requiring power to becut as soon as possible, etc.)).

Referencing FIG. 20, an example apparatus 1900 to reduce or prevent fusedamage and/or a fuse failure is depicted. The example apparatus 1900includes a current event determination circuit 1902, which may determinethat current event 1904 indicates that a fuse threshold value (wear,failure, fatigue, or other threshold value) is exceeded or is predictedto be exceeded. The current event 1904 may be a current, temperature, orany other parameter described, for example, in relation to FIGS. 21, 29,and 30. The example apparatus 1900 further includes a responsedetermination circuit 1906 that determines a system response value1910—for example opening or closing one or more contactors in a fusecircuit (e.g., 2100, 2200, 2300, 2400, or any other fuse circuit orcurrent protection circuit). The apparatus 1900 further includes aresponse implementation circuit 1908 that provides networkcommunications 1912 and/or actuator commands 1914 in response to thesystem response value 1910. For example, the system response value 1910may determine to close one or more contactors, and the actuator commands1914 provides commands to the selected contactors which are responsiveto the actuator commands 1914.

In certain embodiments, operations to bypass and/or engage one or morefuses are performed in coordination with a vehicle battery managementsystem and/or an accelerator pedal input (or other load requestindicator)—for example to time inrush currents that would be experiencedon the fuses, to provide an indication to the battery management systemor other vehicle power systems that momentary un-fused operation isgoing to occur, and/or that a higher fuse limit will be brieflyapplicable. In certain embodiments, during un-fused operation and/orhigher fuse limit operation, the apparatus 1900 may operate a virtualfuse—for example if the experienced current is higher than predicted(e.g., it was predicted to exceed a fuse wear limit but be less than asystem failure limit, but in fact appears that a system failure limitwill be exceeded), the apparatus 1900 may operate to open a main highvoltage contactor, re-engage the fuse, or make another system adjustmentto protect the system in the absence of ordinarily available fusingoperations.

Referencing FIG. 31, an example apparatus 900 to determine an offsetvoltage to adjust a fuse current determination are schematicallydepicted. The example apparatus 900 includes a controller 214 having afuse load circuit 702 that determines that no current is demanded for afuse load 704, and further determines that contactors associated withthe fuse are open. The example apparatus 900 further includes an offsetvoltage(s) determination circuit 906 that determines offset voltages forcomponents in the fuse circuit observed during the no current demandedportion of the operating cycle. In certain embodiments, the contactorsremain open while pre-charge capacitors are still charging after akey-on cycle, whereupon the fuse load circuit 702 determines that nocurrent is demanded for the fuse load 704. In certain embodiments, thecontactors are opened during an operation of the system, and an examplefuse load circuit 702 determines that no current is demanded for a fuseload 704, including potentially waiting for observed voltages to settlebefore determining that no current is demanded for the fuse load 704.

The example apparatus 900 further includes an offset data managementcircuit 914 that stores the offset voltages 906, and communicatescurrent calculation offset voltages 904 for use in the system todetermine current flow through the one or more fuses in the system. Thecurrent calculation offset voltages 904 may be the offset voltages 906for the applicable components, and/or may be processed or conditionedvalues determined from the offset voltages 906.

An example procedure to determine an offset voltage for a fuse currentmeasurement system is described following. The example procedure may beperformed by a system component such as an apparatus 900. Offsetvoltages occur in a controller 214 due to individual offsets of op-ampsand other solid state components in the controller 214, as well as dueto part-to-part variations, temperature drift, and degradation of one ormore components in the system over time. The presence of an offsetvoltage limits the accuracy with which current measurement through afuse is available, and can thereby limit the types of controls anddiagnostics that can be performed in the system.

An example procedure includes an operation to determine that no currentis demanded for a fuse load. Example operations to determine that nocurrent is demanded for a fuse load include a recent key-on or key-offevent for a vehicle (e.g., the vehicle is starting, powering down, is inan accessory position, and/or has not yet engaged power to the fuse ofinterest), observation of the fuse circuit, and/or by a statusobservation provided by another controller in the system (e.g., apowertrain controller is explicitly indicating that no power is beingprovided, is indicating a status inconsistent with power being provided,etc.). An example operation determines that no current is demanded for afuse during a key-off event, and/or within a time period after a key-onevent.

The example procedure further includes an operation to determine theoffset voltage in response to determining that no current is demandedfor the fuse load, and an operation to store the offset voltage. Incertain embodiments, the stored offset voltage is stored in non-volatilememory, for example to be utilized in a subsequent operation of thesystem. In certain embodiments, the offset voltage is stored in avolatile memory and utilized for a current operation cycle. The storedoffset voltage may be replaced when a new value is determined for theoffset voltage, and/or updated in a scheduled manner (e.g., by averagingin or filtering in updated values, by holding new values for subsequentconfirmation before being applied, etc.).

According to the present description, operations to provide an offsetvoltage for components in the fuse circuit, for high confidencedetermination of a fuse current and a fuse resistance value in a PDU 102are described. In certain embodiments, the high confidence determinationof the fuse resistance can be utilized to determine the fuse condition,to provide a high accuracy or high precision determination of currentthrough the fuse and of power consumption by the system 100, and/or toperform system diagnostics, fault management, circuit management, or thelike.

Referencing FIG. 32, an example apparatus 1000 to provide unique currentwaveforms to improve fuse resistance measurement for a PDU 102 isschematically depicted. The example apparatus 1000 includes a fuse loadcircuit 702 that determines that no current is demanded for a fuse load704, and further determines that contactors associated with the fuse areopen. The example apparatus 1000 further includes an injectionconfiguration circuit 606 that determines injection characteristics 608,including frequency, amplitude, and waveform characteristics for testinjection currents through one or more fuses to be tested. The exampleapparatus 1000 further includes an injection control circuit 602 thatinjects current through the fuses according to the injectioncharacteristics 608, and a fuse characterization circuit 1002 thatdetermines one or more fuse resistance(s) 1004 in response to themeasured values 1006 during the test. An example injection controlcircuit 602 waits for the determination of voltage offset values whilethe fuse load 704 is still zero, and the fuse characterization circuit1002 further utilized the voltage offset values in determining the fuseresistance(s) 1004 for the fuses. In certain embodiments, the injectionconfiguration circuit 606 determines injection characteristics 608 inresponse to the characteristics of the system (e.g., the inherentcapacitance and/or inductance of the system, the size of the fuse, thecurrent ranges of the system during operation, and/or the resistancerange and/or desired precision to support operations determinationsutilizing the fuse resistance value). In certain embodiments, a highaccuracy of the fuse resistance supports diagnostics, fuse protectioncontrol, and/or high accuracy on battery state of charge determinations.

In certain embodiments, the fuse characterization circuit 1002determines the fuse resistance(s) 1004 for a given response based upon anumber of current injection events, each of which may have a distinctone or more of an amplitude, frequency, and/or waveform. Additionally oralternatively, frequency sweeping, amplitude sweeping, and/or waveformshape management may be manipulated between injection events and/orwithin a given injection event. The fuse characterization circuit 1002determines the fuse resistance 1004 by determining, for example, anaveraged resistance value determined over the course of the tests. Incertain embodiments, the fuse characterization circuit 1002 utilizesonly a portion of each test window—for example to allow circuit settlingtime after an injection characteristic 608 switch, to allow for theinjection provision circuit (e.g., a solid state op-amp, PWM, relay, orthe like, which is configured to provide a selected current through thefuse circuit) to settle after switching the injection characteristic608, to utilize a selected amount of data from each of the tests (e.g.,for weighting purposes), and the like. In certain embodiments, the fusecharacterization circuit 1002 may exclude outlying data (e.g., two ofthe tests agree, but a third test provides a far different value),and/or data which appears to indicate a rapid change which may appear tonot be valid data. In certain embodiments, filtering, moving averages,rolling buffers, counters for delay in switching values (e.g., toconfirm that a new value appears to be a real change) and the like areapplied by the fuse characterization circuit 1002 to the fuse resistance1004 to smooth changing values of the fuse resistance 1004 over timeand/or to confirm that new information is repeatable. In certainembodiments, each period or a group of periods of a given injectionwaveform may be treated as a separate data point for resistancedeterminations. In certain embodiments, for example where the amplitudeis swept for a given waveform, and/or where the frequency is swept for agiven waveform, the resistance contribution for a given period may alsobe weighted (e.g., higher amplitudes and/or lower frequencies providefor a lower designed area under the current-time curve—see, e.g. FIG.35—which may provide a higher quantity of information about theresistance relative to a lower amplitude and/or higher frequency periodof the same waveform). Additionally or alternatively, measurementconfidence may be dependent upon the frequency and/or amplitude of thecurrent injection, and accordingly resistance determinations for thoseinjection events may be weighted accordingly (e.g., given lower weightwith lower confidence, and higher weight with higher confidence).Additionally or alternatively, conformance of the current injectionsource may be dependent upon the frequency, amplitude, and/or waveformof the current injection, and accordingly resistance determinations forthose injection events may be weighted accordingly, and/or adjusted byfeedback on the injector outlet about what frequency, amplitude, and/orwaveform was actually provided relative to what was commanded.

In certain embodiments, the resistance determinations made by the fusecharacterization circuit 1002, including how the resistance isdetermined and the average indicated by a given test, depend upon thewaveform and other parameters. For example, if a sine wave waveform isutilized, resistance may be determined from the area under the voltageand current curves, from an rms determination (for current and/orvoltage), and/or from high resolution time slices within the voltagedeterminations utilizing the injected current characterization. Otherwaveforms will utilize similar techniques for determining theresistance. If the circuit exhibits significant impedance (e.g. fromlatent capacitance and/or inductance, and/or from components incommunication with the circuit that exhibit impedance), the impedancecan be calculated by varying the frequency and determining the commonimpedance effects between the tests. The availability of multiple testsutilizing varying amplitudes, waveforms, and/or frequency values ensuresthat high accuracy can be determined even for circuits with complexeffects or that exhibit changes due to age, degradation, or componentservicing or replacing. Further, adjusting the frequency throughout thetests, and/or sweeping the frequency for a given amplitude or waveformcan assist in de-coupling the phase-shifted aspects of impedance (e.g.,capacitance effects versus inductance effects) to more confidentlydetermine a resistance for the fuse. Typically for a fuse circuit havinga closely coupled current source, impedance will be minimal. The desireddegree of accuracy for the resistance measurement, which may depend uponthe diagnostics, battery state of charge algorithms, and/or fuseprotection algorithms in use on the system, may also affect whetherimpedance must be accounted for, and accordingly the selection ofinjection characteristics 608 utilized.

It can be seen that the use of multiple injection characteristics 608during a test leverages comparisons between the tests to de-couplesystem characteristics from the resistance determination, provides for arange of system excitement parameters to ensure that systemcharacteristics do not dominate a single test, and overall increase theamount of information available for a test to develop statisticalconfidence in the determined resistance value. Also, manipulation ofinjection characteristics 608 allows for better averaging—for example toprepare waveforms with high confidence that the resistance calculationis correct such as utilizing frequency values that avoid resonant orharmonic frequencies in the system, provide a large area under thecurrent-time (or voltage-time) curve, and/or provide for a stabilizedsystem during the test to ensure that measurement is correct.

Additionally or alternatively, the fuse characterization circuit 1002adjusts digital filter values before the test, between changes ininjection characteristics 608 for the test, and/or dynamically duringthe test (e.g., where a frequency sweep, amplitude sweep, and/orwaveform change is utilized during a given injection event). In certainembodiments, the measurement of the voltage out of the filter circuitutilizes a high-pass filter to determine the injection voltage (and/orcurrent), and the filter characteristics can be manipulated in real timeto provide for an appropriate filter, such as cutoff frequencies. Theutilization of digital filters for measurement can also eliminate phaselags between different filter types—such as a low pass filter and a highpass filter (e.g., where the low pass filter determines base powercurrent during operation, and/or confirms that base power currentremains zero or negligible during the test).

Referencing FIG. 35, an illustrative injection characteristic 608 isdepicted for an example test. The injection characteristic 608 includesa first injection portion having an amplitude of 10 current units (e.g.,amps—but any current units are contemplated herein), a sinusoidalwaveform, and a period of approximately 150 time units (e.g., executioncycles of the controller 214, milliseconds, seconds, or any otherparameter). The units and values depicted in FIG. 35 are non-limitingexamples, and are used to illustrate that sequential changes in theinjection characteristic 608 can be applied. The injectioncharacteristic 608 includes a second injection portion having anamplitude of 15 current units, a sawtooth waveform, and a period ofapproximately 250 time units. The injection characteristic 608 furtherincludes a third injection portion having an amplitude of 5 currentunits, a near square waveform (a slightly trapezoidal waveform isdepicted), and a period of approximately 80 time units. The embodimentdepicted in FIG. 35 is non-limiting, and other features may be added tothe test, including more or less than three distinct waveforms, gapsbetween waveforms, and adjustments within a waveform (includingsweeping, stepping, or otherwise adjusting frequency or amplitude,and/or adjusting the waveform itself). The example of FIG. 35 shows atrajectory reversal between the first and second injectioncharacteristic (e.g., decreasing sine wave to increasing sawtooth wave)and a continuation of the trajectory between the second and thirdinjection characteristic (e.g., decreasing sawtooth wave to anincreasing square wave), although any possibilities, including stepchanges of the current and the like, are contemplated herein.

Referencing FIG. 33, an example procedure 1100 to provide unique currentwaveforms to improve fuse resistance measurement for a PDU 102 isschematically depicted. The procedure 1100 includes an operation 1102 toconfirm that the contactors are open (and/or to confirm that the fuseload is zero or intended to be zero), and an operation 1104 to perform anull voltage offset determination—for example to determine offsetvoltage of op-amps and other components of the controller 214 and/or inthe system 100 electrically coupled to the fuse circuit. An exampleoperation 1102 is commenced during a key-on or system startup event withthe contactors open, although any operating condition meeting thecriteria for operation 1102 may be utilized. The procedure 1100 furtherincludes an operation 1106 to conduct a number of injectionsequences—for example three sequences each having a distinct frequency,amplitude, and waveform. The operation 1106 may include more than threesequences, and one or more of the sequences may share a frequency, anamplitude, and/or a waveform. The operation 1106 may be configured toperform as many sequences as desired, and may be carried over multipletests (e.g., where a test is interrupted by operations of the system orexceeds a desired time, the test may be continued on a later sequenceinitiated by operation 1102). The procedure 1100 further includes anoperation 1108 to determine fuse resistance values for one or more ofthe fuses in the system. The procedure 1100 may be operated onindividual fuses where hardware in the system is configured to supportthat, including across subsets of the fuses or the like.

Referencing FIG. 34, an example procedure 1106 to conduct a number ofinjection sequences is depicted. The example procedure 1106 includes anoperation 1202 to adjust injection characteristics for a currentinjection source associated with the fuse(s) to be tested, and anoperation 1204 to adjust filtering characteristics for one or moredigital filters associated with measuring voltage and/or current valueson the filtering circuit. The procedure 1106 further includes anoperation 1206 to perform the injection sequence in response to theinjection characteristic, and an operation 1208 to perform the filtering(e.g., thereby measuring the current and/or voltage on the fuse circuitin response to the injection events). The procedure 1106 furtherincludes an operation 1210 to determine if the current injectionsequence is completed, returning to continue the injection event atoperation 1206 until the sequence is complete (at operation 1210determining YES). For example, referencing FIG. 35, at time step 200 theoperation 1210 would determine NO, as the sine wave portion of the testis still being performed. If the operation 1210 determines YES (e.g., inFIG. 35, where the sine wave portion transitions to the sawtoothportion), the procedure 1106 includes an operation 1212 to determinewhether another injection sequence is desired, and returns to operation1202 to adjust the injection sequence in response to operation 1212determining YES (e.g., in FIG. 9, where the sine wave portion iscompleted and the sawtooth portion commences). In response to theoperation 1212 determining NO (e.g., where the square wave portion iscompleted, and no further sequences are scheduled in the test), theprocedure 1106 completes—for example returning to operation 1108 todetermine the fuse resistance value from the test.

According to the present description, operations to provide varyingwaveforms for current injection, thereby enhancing determination of thefuse resistance value in a PDU 102 are described. In certainembodiments, the high confidence determination of the fuse resistancecan be utilized to determine the fuse condition, to provide a highaccuracy or high precision determination of current through the fuse andof power consumption by the system 100, and/or to perform systemdiagnostics, fault management, circuit management, or the like.

Referencing FIG. 36, an example system includes a vehicle 3602 having amotive electrical power path 3604; and a power distribution unit 3606having a current protection circuit 3608 disposed in the motiveelectrical power path 3604. The example current protection circuit 3608includes a first leg 3610 of the current protection circuit 3608including a pyro-fuse 3620 (e.g., a controllable activated fuse that canbe commanded to activate and open the first leg of the currentprotection circuit; a second leg 3612 of the current protection circuit3608 including a thermal fuse 3622; and where the first leg 3610 and thesecond leg 3612 are coupled in a parallel arrangement (e.g., in asimilar manner to the depiction of any one of FIGS. 26 to 28). Theexample system includes a controller 3614 having a current detectioncircuit 3616 structured to determine a current flow through the motiveelectrical power path 3614, and a pyro-fuse activation circuit 3618structured to provide a pyro-fuse activation command in response to thecurrent flow exceeding a threshold current flow value. The pyro-fuse3620 is responsive to the pyro-fuse activation command, for example toactivate and open the second leg 3612 upon command Upon activation ofthe pyro-fuse 3620, the second leg 3612 is opened, providing for normalfused operation on the first leg 3610 (e.g., thermal failure of thethermal fuse 3622 thereby opens the motive electrical power path 3604),and/or opening the motive electrical power path 3604 directly when acontactor 3626 in series with the thermal fuse 3622 is already opened.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where a first resistance through the first leg3620 and a second resistance through the second leg 3612 are configuredsuch that a resulting current through the second leg 3612 after thepyro-fuse 3620 activates is sufficient to activate the thermal fuse3622. For example, a high current event may be experienced such that, ifthe second leg 3622 were not drawing a portion of the high currentevent, the thermal fuse 3622 would be activated. In the example, theopening of the second leg 3612 will cause the current in the first leg3620 to increase and activate the thermal fuse 3622. An example includesa resistor 3624 coupled in a series arrangement with the thermal fuse3622, such that a resulting current through the second leg 3612 afterthe pyro-fuse 3620 activates is below a second threshold current flowvalue. For example, an under-sized thermal fuse 3622 may be utilized inthe system, with the operating current through the second leg 3612reduced by the resistor 3624. When the pyro-fuse 3620 opens, the currentthrough the second leg 3612 is increased, but still reduced by theresistor 3624 to prevent high current transients in the motiveelectrical power path 3604, and still allowing sufficient currentthrough the second leg 3612 to activate the thermal fuse 3622.

An example system includes a contactor coupled 3626 in a seriesarrangement with the thermal fuse 3622, the controller further includinga contactor activation circuit 3628 structured to provide a contactoropen command in response to at least one of the pyro-fuse activationcommand or the current flow exceeding the threshold current flow value.In certain embodiments, the contactor 3626 coupled in the seriesarrangement with the thermal fuse 3622 allows for control of the currentthrough the second leg 3612, including opening the second leg 3612 toopen the motive electrical power path 3604 in combination withactivation of the pyro-fuse 3620. The resistor 3624 may additionally beutilized with the contactor 3626, for example reducing the currentthrough the second leg 3612 when the pyro-fuse 3620 activates (e.g.,where contactor 3626 dynamics may be slower than the pyro-fuse 3620dynamics). An example includes a resistor 3624 coupled in a seriesarrangement with the pyro-fuse 3620, such that a resulting currentthrough the first leg 3610 after the thermal fuse 3622 activates isbelow a second threshold current flow value—for example to reduce thecurrent through the motive electrical power path 3604 if the thermalfuse 3622 activates when the pyro-fuse 3620 has not already activated(e.g., an unmeasured current spike, and/or a current spike occurringafter a controller has failed and is unable to command the pyro-fuse3620 to open). An example system includes a second thermal fuse (notshown) coupled in a series arrangement with the pyro-fuse 3620, suchthat a resulting current through the first leg 3610 after the thermalfuse 3622 activates is sufficient to activate the second thermal fuse.For example, the use of a second thermal fuse provides for all branchesof the motive electrical power path 3604 to have fuses with physicalresponses present, avoiding failures due to loss of ability to detectcurrents in the system or to command a pyro-fuse 3620 to activate. Inthe example, the sizing of the thermal fuse 3622 and the second thermalfuse can be made to avoid thermal wear during normal operations, butsufficient such that either thermal fuse 3622 will readily protect thesystem when the other leg (the first leg 3610 or second leg 3612) isopened during high current events. It can be seen that embodiments ofthe system depicted in FIG. 36 provide for both the high controllabilityof a pyro-fuse 3620 to disconnect the power, along with the robustprotection of a thermal fuse that will physically respond to highcurrent values regardless of failures in current sensing or controlleroperation, as may occur during a system failure, vehicle accident, etc.Additionally, the utilization of the two legs 3610, 3612, includingpotentially current management therethrough with resistor(s) 3624 and/orcontactor(s) 3626, allows for the utilization of fuses that can be sizedto avoid thermal wear and/or nuisance failures over the life of thevehicle, while still providing for reliable power disconnection for highcurrent events.

Referencing FIG. 37, an example procedure includes an operation 3702 todetermine a current flow through a motive electrical power path of avehicle; an operation 3704 to direct the current flow through a currentprotection circuit having a parallel arrangement, with a pyro-fuse on afirst leg of the current protection circuit and a thermal fuse on asecond leg of the current protection circuit; and an operation 3706 toprovide a pyro-fuse activation command in response to the current flowexceeding a threshold current flow value.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to configure a firstresistance through the first leg and a second resistance through thesecond leg such that a resulting current through the second leg afterthe pyro-fuse activates is sufficient to activate the thermal fuse. Anexample procedure includes an operation to configure a second resistancethrough the second leg such that a resulting current through the secondleg after the pyro-fuse activates is below a second threshold currentflow value. An example procedure includes an operation to a contactorcoupled in a series arrangement with the thermal fuse, the procedurefurther including providing a contactor open command in response to atleast one of providing the pyro-fuse activation command or the currentflow exceeding the threshold current flow value; and/or an operation toconfigure a second resistance through the second leg such that aresulting current through the second leg after the pyro-fuse activatesis below a second threshold current flow value. An example procedurefurther including a resistor coupled in a series arrangement with thepyro-fuse such that a resulting current through the first leg after thethermal fuse activates is below a second threshold current flow value;and/or further including a second thermal fuse coupled in a seriesarrangement with the pyro-fuse, such that a resulting current throughthe first leg after the thermal fuse activates is sufficient to activatethe second thermal fuse.

Referencing FIG. 38, an example system includes a vehicle 3802 having amotive electrical power path 3804; a power distribution unit 3806 havinga current protection circuit 3808 disposed in the motive electricalpower path 3804, where the current protection circuit includes a firstleg 3810 of the including a thermal fuse 3820 and a second leg 3812including a contactor 3822. The first leg 3810 and the second leg 3812are coupled in a parallel arrangement. The system includes a controller3614 having a current detection circuit 3816 structured to determine acurrent flow through the motive electrical power path 3804; and a fusemanagement circuit 3818 structured to provide a contactor activationcommand in response to the current flow. The contactor 3822 isresponsive to the contactor activation command.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the contactor 3822 is open during nominaloperations of the vehicle, and where the fuse management circuit isstructured to provide the contactor activation command as a contactorclosing command in response to determining that the current flow is aabove a thermal wear current for the thermal fuse 3820; and/or where thefuse management circuit is further structured to provide the contactoractivation command as the contactor closing command in response todetermining that the current flow is below a current protection valuefor the motive electrical power path 3804. An example system includeswhere the contactor 3822 is closed during nominal operations of thevehicle, and where the fuse management circuit is structured to providethe contactor activation command as a contactor opening command inresponse to determining that the current flow is above a currentprotection value for the motive electrical power path 3804. An examplesystem includes where the fuse management circuit is further structuredto provide the contactor activation command in response to the currentflow by performing at least one operation selected from the operationsconsisting of: responding to a rate of change of the current flow;responding to a comparison of the current flow to a threshold value;responding to one of an integrated or accumulated value of the currentflow; and responding to one of an expected or a predicted value of anyof the foregoing. It can be seen that the embodiments of the systemdepicted in FIG. 38 allow for the utilization of an oversized fuse 3820that will experienced reduced wear and increased life, while stillallowing for circuit protection for moderate overcurrent (e.g.,utilizing the contactor) and fused protection for high overcurrentvalues. It can be seen that the embodiments of the system depicted FIG.38 allow for utilization of a nominally sized or undersized fuse 3820that can reliably open the circuit at moderate overcurrent values, butexperience reduced wear and increased life (e.g., by sharing currentthrough the contactor branch).

Referencing FIG. 39, an example procedure includes an operation 3902 todetermine a current flow through a motive electrical power path of avehicle; an operation 3904 to direct the current flow through a currentprotection circuit having a parallel arrangement, with a thermal fuse ona first leg of the current protection circuit and a contactor on asecond leg of the current protection circuit; and an operation 3906 toprovide a contactor activation command in response to the current flow.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to close the contactorin response to the current flow. An example procedure includes anoperation to determine that the current flow is below a currentprotection value for the motive electrical power path before the closingthe contactor. An example procedure includes at least one operationselected from the operations consisting of: responding to a rate ofchange of the current flow; responding to a comparison of the currentflow to a threshold value; responding to one of an integrated oraccumulated value of the current flow; and responding to one of anexpected or a predicted value of any of the foregoing. An exampleprocedure includes an operation to open the contactor in response to thecurrent flow; an operation to determine that the current flow is above acurrent protection value for the motive electrical power path beforeopening the contactor; and/or an operation to open the contactorincluding performing any one or more of: responding to a rate of changeof the current flow; responding to a comparison of the current flow to athreshold value; responding to one of an integrated or accumulated valueof the current flow; and responding to one of an expected or a predictedvalue of any of the foregoing.

Referencing FIG. 40, an example system includes a vehicle 4002 having amotive electrical power path 4004; a power distribution unit 4006 havinga current protection circuit 4008 disposed in the motive electricalpower path 4004, where the current protection circuit includes a firstleg 4010 of the current protection circuit 4008 including a thermal fuse4020 and a second leg 4012 of the current protection circuit 4008including a solid state switch 4022. The first leg 4010 and the secondleg 4012 are coupled in a parallel arrangement. The example systemincludes a controller 4014 including a current detection circuit 4016structured to determine a current flow through the motive electricalpower path 4004 and a fuse management circuit 4018 structured to providea switch activation command in response to the current flow. The solidstate switch 4022 is responsive to the switch activation command. Incertain embodiments, the system includes a contactor 4024 coupled to thecurrent protection circuit 4008, where the contactor 4024 in the openposition disconnects the current protection circuit 4008 (e.g., thecontactor 4024 in series with both legs 4010, 4012), and/or thecontactor 4024 in series with the solid state switch 4022 on the secondleg 4012). Any contactor described throughout the present disclosuremay, in certain embodiments, be a solid state switch instead of, or inseries with, a conventional contactor device. Solid state switches areknown to have rapid response and are robust to opening during highcurrent events. However, solid state switches also experience a smallleakage current, which may be acceptable in certain embodiments, or notacceptable in other embodiments. In certain embodiments, the utilizationof a conventional contactor with a solid state switch allows for therapid response time and survivability of the solid state switch, as wellas the enforced zero current of a conventional contactor. In certainembodiments, the solid state switch is utilized to open the circuitfirst, and then the conventional contactor opens the circuit second,allowing for the avoidance of conditions where the conventionalcontactor opens under high current conditions.

Referencing FIG. 41, an example procedure includes an operation 4102 todetermine a current flow through a motive electrical power path of avehicle; an operation 4104 to direct the current flow through a currentprotection circuit having a parallel arrangement, with a thermal fuse ona first leg of the current protection circuit and a solid state switchon a second leg of the current protection circuit; and an operation 4106to provide a switch activation command in response to the current flow.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to close the solid stateswitch in response to the current flow; and/or determine that thecurrent flow is below a current protection value for the motiveelectrical power path before the closing the solid state switch. Forexample, a current flow value or transient may be sufficiently high tocause degradation of the thermal fuse, but lower than a threshold wherea system protection response from the thermal fuse is required. Incertain embodiments, closing the solid state switch reduces the currentflow and/or transient through the thermal fuse, reducing the wear and/ora nuisance failure of the thermal fuse. An example procedure includes anoperation to close the solid state switch includes performing at leastone operation such as: responding to a rate of change of the currentflow; responding to a comparison of the current flow to a thresholdvalue; responding to one of an integrated or accumulated value of thecurrent flow; and responding to one of an expected or a predicted valueof any of the foregoing. An example procedure includes an operation toopen the solid state switch in response to the current flow; and/ordetermine that the current flow is above a current protection value forthe motive electrical power path before opening the solid state switch.An example procedure includes an operation to open the solid stateswitch includes performing at least one operation selected from theoperations consisting of: responding to a rate of change of the currentflow; responding to a comparison of the current flow to a thresholdvalue; responding to one of an integrated or accumulated value of thecurrent flow; and responding to one of an expected or a predicted valueof any of the foregoing. An example procedure includes an operation toopen a contactor after the opening the solid state switch, where openingthe contactor disconnects one of the current protection circuit or thesecond leg of the current protection circuit.

Referencing FIG. 42, an example system includes a vehicle having amotive electrical power path 4204; a power distribution unit 4206 havinga current protection circuit 4208 disposed in the motive electricalpower path 4204, where the current protection circuit includes a firstleg 4220 of the current protection circuit 4208 including a firstthermal fuse 4220, a second leg 4212 of the current protection circuit4208 including a second thermal fuse 4222 and a contactor 4224, andwhere the first leg 4220 and the second leg 4212 are coupled in aparallel arrangement. The example system includes a controller,including: a current detection circuit 4216 structured to determine acurrent flow through the motive electrical power path 4204; and a fusemanagement circuit 4218 structured to provide a contactor activationcommand in response to the current flow. The contactor 4224 isresponsive to the contactor activation command.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the contactor 4224 is open during nominaloperations of the vehicle, and where the fuse management circuit 4218 isstructured to provide the contactor activation command as a contactorclosing command in response to determining that the current flow is aabove a thermal wear current for the first thermal fuse 4220. An examplesystem includes the fuse management circuit 4218 further structured toprovide the contactor activation command as a contactor closing commandin response to determining that the current flow is below a currentprotection value for the motive electrical power path 4204. An examplesystem includes a vehicle operating condition circuit 4226 structured todetermine an operating mode for the vehicle (e.g., moving, stopped, highperformance, high economy, charging, quick charging, etc.), and wherethe fuse management circuit 4218 is further structured to provide thecontactor activation command in response to the operating mode. Anexample system includes the fuse management circuit 4218 furtherstructured to provide the contactor activation command as a contactorclosing command in response to the operating mode including at least oneoperating mode selected from the operating modes consisting of: acharging mode; a quick charging mode; a high performance mode; a highpower request mode; an emergency operation mode; and/or a limp homemode. An example system includes where the contactor 4224 is closedduring nominal operations of the vehicle, and where the fuse managementcircuit 4218 is structured to provide the contactor activation commandas a contactor opening command in response to determining that thecurrent flow is above a current protection value for the motiveelectrical power path 4204. An example system includes where thecontactor is closed during nominal operations of the vehicle, and wherethe fuse management circuit 4218 is structured to provide the contactoractivation command as a contactor opening command in response to theoperating mode; and/or where the fuse management circuit 4218 is furtherstructured to provide the contactor activation command as a contactoropening command in response to the operating mode including at least oneof an economy mode or a service mode. For example, during certainoperating conditions such as an economy mode or during a service event,a reduced maximum power throughput through the motive electrical powerpath 4204 may be enforced, where the opening of the contactor 4224 isutilized to provide configured fuse protection for the reduced maximumpower throughput.

Referencing FIG. 43, an example procedure includes an operation 4302 todetermine a current flow through a motive electrical power path of avehicle; an operation 4304 to direct the current flow through a currentprotection circuit having a parallel arrangement, with a first thermalfuse on a first leg of the current protection circuit and a secondthermal fuse and a contactor on a second leg of the current protectioncircuit; and an operation 4306 to provide a contactor activation commandin response to the current flow.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to close the contactorin response to the current flow being above a thermal wear current forthe first thermal fuse; and/or closing the contactor further in responseto the current flow being below a current protection value for themotive electrical power path. An example procedure includes an operationto determine an operating mode for the vehicle, and providing thecontactor activation command further in response to the operating mode.An example procedure includes an operation to provide the contactoractivation command as a contactor closing command in response to theoperating mode including at least one operating mode selected from theoperating modes consisting of: a charging mode; a high performance mode;a high power request mode; an emergency operation mode; and a limp homemode. An example procedure includes an operation to provide thecontactor activation command as a contactor opening command in responseto determining that the current flow is above a current protection valuefor the motive electrical power path; and/or provide the contactoractivation command as a contactor opening command in response to theoperating mode including at least one of an economy mode or a servicemode.

Referencing FIG. 44, an example system includes a vehicle 4402 having amotive electrical power path 4404; a power distribution unit 4406 havinga current protection circuit 4408 disposed in the motive electricalpower path 4404, where the current protection circuit includes: a firstleg 4410 of the current protection circuit 4408 including a firstthermal fuse 4420 and a first contactor 4424; a second leg 4412 of thecurrent protection circuit 4408 including a second thermal fuse 4422 anda second contactor 4426; and where the first leg 4410 and the second leg4412 are coupled in a parallel arrangement. The example system includesa controller 4414 including a current detection circuit 4416 structuredto determine a current flow through the motive electrical power path4404; and a fuse management circuit 4418 structured to provide aplurality of contactor activation commands in response to the currentflow. The first contactor 4424 and the second contactor 4426 areresponsive to the contactor activation commands, thereby providing aselected configuration of the current protection circuit 4408.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the current protection circuit furtherincludes: one or more additional legs 4413, where each additional leg4413 includes an additional thermal fuse 4423 and an additionalcontactor 4428; and where each additional contactor 4428 is furtherresponsive to the contactor activation commands, thereby providing theselected configuration of the current protection circuit 4408. Anexample system includes a vehicle operating condition circuit 4430structured to determine an operating mode for the vehicle, and where thefuse management circuit 4418 is further structured to provide thecontactor activation commands in response to the operating mode. Anexample fuse management circuit 4418 is further structured to determinean active current rating for the motive electrical power path 4404 inresponse to the operating mode, and to provide the contactor activationcommands in response to the active current rating. An example systemincludes where the first leg 4410 of the current protection circuit 4408further includes an additional first contactor 4427 in a parallelarrangement with the first thermal fuse 4420, where the currentdetection circuit 4416 is further structured to determine a first legcurrent flow, where the fuse management circuit 4418 is furtherstructured to provide the contactor activation commands further inresponse to the first leg current flow, and where the additional firstcontactor 4427 is responsive to the contactor activation commands. Anexample system includes the additional first contactor 4427 being openduring nominal operations of the vehicle, and where the fuse managementcircuit 4418 is structured to provide the contactor activation commandsincluding an additional first contactor closing command in response todetermining that the first leg current flow is a above a thermal wearcurrent for the first thermal fuse 4420. An example system includes thefuse management circuit 4418 structured to provide the additional firstcontactor closing command in response to determining at least one of:that the first leg current flow is below a first leg current protectionvalue, or that the current flow is below a motive electrical power pathcurrent protection value. An example system includes where theadditional first contactor 4427 is closed during nominal operations ofthe vehicle, and where the fuse management circuit 4418 is structured toprovide the contactor activation commands including an additional firstcontactor opening command in response to determining at least one of:that the first leg current flow is above a first leg current protectionvalue, or that the current flow is above a motive electrical power pathcurrent protection value. The example system may further includeadditional contactors 4428 positioned on any one or more of the legs4410, 4412, 4413. Any one or more of the contactors 4424, 4426, 4428 maybe configured in series and/or parallel with the associated thermal fuse4420, 4422, 4423 on the associated leg.

Referencing FIG. 45, an example procedure includes an operation 4502 todetermine a current flow through a motive electrical power path of avehicle; an operation 4504 to direct the current flow through a currentprotection circuit having a parallel arrangement, with a first thermalfuse and a first contactor on a first leg of the current protectioncircuit, and a second thermal fuse and a second contactor on a secondleg of the current protection circuit; and an operation 4506 to providea selected configuration of the current protection circuit in responseto the current flow through the motive electrical power path of thevehicle, where providing the selected configuration includes providing acontactor activation command to each of the first contactor and thesecond contactor.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure includes an operation further including at least oneadditional leg of the current protection circuit, each additional leg ofthe current protection circuit having an additional thermal fuse and anadditional contactor, and where the providing the selected configurationof the current protection circuit includes providing a contactoractivation command to each additional contactor. An example procedureincludes an operation to determine an operating mode for the vehicle,and providing the selected configuration further in response to theoperating mode; and/or an operation to determine an active currentrating for the motive electrical power path in response to the operatingmode, and where providing the selected configuration of the currentprotection circuit is further in response to the active current rating.An example procedure includes an operation to determine an activecurrent rating for the motive electrical power path, and where providingthe selected configuration of the current protection circuit is furtherin response to the active current rating. An example procedure includesan operation where the first leg of the current protection circuitfurther includes an additional first contactor in a parallel arrangementwith the first thermal fuse, the procedure further including:determining a first leg current flow, and where providing the selectedconfiguration further includes providing a contactor activation commandto the additional first contactor; an operation to close the additionalfirst contactor in response to determining that the first leg currentflow is a above a thermal wear current for the first thermal fuse; anoperation to close the additional first contactor further in response todetermining at least one of: that the first leg current flow is below afirst leg current protection value, or that the current flow is below amotive electrical power path current protection value; and/or anoperation to open the additional first contactor in response todetermining at least one of: that the first leg current flow is above afirst leg current protection value, or that the current flow is above amotive electrical power path current protection value.

Referencing FIG. 46, an example system includes a vehicle 4602 having amotive electrical power path 4604; a power distribution unit 4606 havinga current protection circuit 4608 disposed in the motive electricalpower path 4604, where the current protection circuit 4608 includes afuse 4610. The example system further includes a controller 4614including a fuse status circuit 4616 structured to determine a fuseevent value; and a fuse management circuit 4618 structured to provide afuse event response based on the fuse event value.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes a fuse life description circuit 4619 structuredto determine a fuse life remaining value, where the fuse event valueincludes a representation that the fuse life remaining value is below athreshold value, and where the fuse management circuit 4618 is furtherstructured to provide the fuse event response further based on the fuselife remaining value. Example and non-limiting operations to provide thefuse event include providing a fault code and/or a notification of thefuse event value, for example to a datalink, another controller in thesystem, as a service notification, to a fleet owner (e.g., a maintenancemanager), stored as a fault code for service access, and/or as anotification to an operator, a mobile device, a service report, or thelike. Example and non-limiting operations to provide the fuse eventresponse include: adjusting a maximum power rating for the motiveelectrical power path; adjusting a maximum power slew rate for themotive electrical power path; and/or adjusting a configuration of thecurrent protection circuit. An example system includes where the currentprotection circuit 4606 further includes a contactor 4612 coupled in aparallel arrangement to the fuse 4610; and/or where the fuse managementcircuit 4618 is further structured to provide a contactor activationcommand in response to the fuse event value. In the example, thecontactor 4612 is responsive to the contactor activation command. Anexample system includes where the fuse management circuit 4618 isfurther structured to provide the contactor activation command as acontactor closing command in response to the fuse event value being oneof a thermal wear event or an imminent thermal wear event for the fuse4610. An example system includes where the fuse management circuit 4618is further structured to adjust a current threshold value for thecontactor activation command in response to the fuse life remainingvalue (e.g., open the contactor at a lower or higher threshold as thefuse ages). An example system includes a cooling system 4620 at leastselectively thermally coupled to the fuse, and a cooling systeminterface 4622 (e.g., hardware interfaces such as flow couplings,valves, etc., and/or communication interfaces such as network commands,electrical couplings, etc.); and/or where providing the fuse eventresponse includes adjusting a cooling system interface 4622 for thecooling system 4620 in response to the fuse life remaining value (e.g.,increasing active cooling capability to the fuse as the fuse ages).

Referencing FIG. 47, an example procedure includes an operation 4702 todetermine a fuse event value for a fuse disposed in a current protectioncircuit, the current protection circuit disposed in a motive electricalpower path of a vehicle; and an operation 4704 to provide a fuse eventresponse based on the fuse event value.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to determine a fuse liferemaining value, where the fuse event value includes a representationthat the fuse life remaining value is below a threshold value, andproviding the fuse event response further based on the fuse liferemaining value; an operation to provide the fuse event responseincludes providing at least one of a fault code or a notification of thefuse event value; an operation to provide the fuse event responseincludes adjusting a maximum power rating for the motive electricalpower path; an operation to provide the fuse event response includesadjusting a maximum power slew rate for the motive electrical powerpath; an operation to provide the fuse event response includes adjustinga configuration of the current protection circuit. An example procedureincludes an operation where the current protection circuit furtherincludes a contactor coupled in a parallel arrangement to the fuse;where the fuse management circuit is further structured to provide acontactor activation command in response to the fuse event value; andwhere the contactor is responsive to the contactor activation command;where the fuse management circuit is further structured to provide thecontactor activation command as a contactor closing command in responseto the fuse event value including one of a thermal wear event or animminent thermal wear event for the fuse; and/or where the fusemanagement circuit is further structured to adjust a current thresholdvalue for the contactor activation command in response to the fuse liferemaining value. An example procedure includes an operation to providethe fuse event response includes adjusting a cooling system interfacefor a cooling system at least selectively thermally coupled to the fusein response to the fuse life remaining value. An example procedureincludes an operation to provide the fuse event response includesproviding at least one of a fault code or a notification of the fuseevent value. An example procedure includes an operation to determine anaccumulated fuse event description in response to the fuse eventresponse, and storing the accumulated fuse event description. An exampleprocedure includes an operation to provide the accumulated fuse eventdescription, where providing the accumulated fuse event descriptionincludes at least one of providing at least one of a fault code or anotification of the accumulated fuse event description; and an operationto provide the accumulated fuse event description in response to atleast one of a service event or a request for the accumulated fuse eventdescription.

Referencing FIG. 48, an example system includes a vehicle 4802 having amotive electrical power path 4804 and at least one auxiliary electricalpower path 4805; a power distribution unit 4806 having a motive currentprotection circuit 4808 disposed in the motive electrical power path4804, the motive current protection circuit including a fuse; and anauxiliary current protection circuit 4810 disposed in each of the atleast one auxiliary electrical power paths 4805, each auxiliary currentprotection circuit 4810 including an auxiliary fuse (not shown). Thesystem includes a controller 4814 including: a current determinationcircuit 4816 structured to interpret a motive current valuecorresponding to the motive electrical power path, and an auxiliarycurrent value corresponding to each of the at least one auxiliaryelectrical power paths.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes a motive current sensor 4824 electricallycoupled to the motive electrical power path 4804, where the motivecurrent sensor 4824 is configured to provide the motive current value.An example system includes at least one auxiliary current sensor 4826each electrically coupled to one of the at least one auxiliaryelectrical power paths, each auxiliary current sensor 4826 configured toprovide the corresponding auxiliary current value. An example systemincludes where the controller 4814 further includes a vehicle interfacecircuit 4828, the vehicle interface circuit structured to provide themotive current value to a vehicle network (not shown); where the vehicleinterface circuit 4828 is further structured to provide the auxiliarycurrent value corresponding to each of the at least one auxiliaryelectrical power paths 4805 to the vehicle network; and/or furtherincluding a battery management controller (not shown) configured toreceive the motive current value from the vehicle network. In certainembodiments, one or more of the motive current value and/or theauxiliary current value(s) are provided by a fuse current model, forexample determined in accordance with a load voltage drop across thefuse and/or a fuse resistance (and/or fuse dynamic resistance or fuseimpedance) value determined from an injected current operation acrossthe fuse. The utilization of a fuse current model can provide for higheraccuracy (e.g. relative to a moderately capable or inexpensive currentsensor) and/or faster response time for current determination than asensor. In certain embodiments, a current sensor may be combined withthe utilization of a fuse current model, for example favoring one or theother of the sensor or the model depending upon the operatingconditions, and the expected accuracies of the sensor or the model inview of the operating conditions.

Referencing FIG. 49, an example procedure includes an operation 4902 toprovide a power distribution unit having a motive current protectioncircuit and at least one auxiliary current protection circuit; anoperation 4904 to power a vehicle motive electrical power path throughthe motive current protection circuit; an operation 4906 to power atleast one auxiliary load through a corresponding one of the at least oneauxiliary current protection circuit; an operation 4908 to determine amotive current value corresponding to the motive electrical power path;and an operation 4910 to determine an auxiliary current valuecorresponding to each of the at least one auxiliary current protectioncircuits.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to provide the motivecurrent value to a vehicle network; and/or an operation to receive themotive current value with a battery management controller.

Referencing FIG. 50, an example system includes a vehicle 5002 having amotive electrical power path 5004; a power distribution unit 5006 havinga current protection circuit 5008 disposed in the motive electricalpower path 5004, where the current protection circuit includes: athermal fuse 5020; and a contactor 5022 in a series arrangement with thethermal fuse 5020. The system further includes a controller 5014,including: a current detection circuit 5016 structured to determine acurrent flow through the motive electrical power path 5004; and a fusemanagement circuit 5018 structured to provide a contactor activationcommand in response to the current flow; and where the contactor 5022 isresponsive to the contactor activation command.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the thermal fuse 5020 includes a currentrating that is higher than a current corresponding to a maximum powerthroughput of the motive electrical power path 5004 (e.g., where thefuse is sized to avoid wear or degradation up to the maximum powerthroughput, where the fuse is sized to accommodate a higher power ratingand/or a quick charging power throughput, etc.). An example systemincludes where the thermal fuse 5020 includes a current rating that ishigher than a current corresponding to a quick charging power throughputof the motive electrical power path 5004. An example system includeswhere the contactor 5020 includes a current rating that is higher than acurrent corresponding to a maximum power throughput of the motiveelectrical power path 5004. In certain embodiments, the currentcorresponding to the maximum power throughput of the motive electricalpower path 5004 may correspond to a current at nominal voltage, and/or acurrent at a degraded and/or failure mode voltage (e.g., as the batterypack ages, and/or if one or more cells are deactivated). An examplesystem includes where the contactor 5022 includes a current rating thatis higher than a current corresponding to a quick charging powerthroughput of the motive electrical power path 5004. An example systemincludes where the fuse management circuit 5018 is further structured toprovide the contactor activation command as a contactor opening commandin response to the current flow indicating a motive electrical powerpath protection event. An example current detection circuit 5016determines the motive electrical power path protection event byperforming at least one operation such as: responding to a rate ofchange of the current flow; responding to a comparison of the currentflow to a threshold value; responding to one of an integrated oraccumulated value of the current flow; and/or responding to one of anexpected or a predicted value of any of the foregoing.

Referencing FIG. 51, an example procedure includes an operation 5102 topower a motive electrical power path of a vehicle through a currentprotection circuit including a thermal fuse and a contactor in a seriesarrangement with the thermal fuse; and an operation 5104 to determine acurrent flow through the motive electrical power path; and an operationto selectively open the contactor in response to the current flow.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to provide the thermalfuse having a current rating that is higher than a current correspondingto a maximum power throughput of the motive electrical power path. Anexample procedure includes an operation to provide the thermal fusehaving a current rating that is higher than a current corresponding to aquick charging power throughput of the motive electrical power path. Anexample procedure includes an operation to provide the contactor havinga current rating that is higher than a current corresponding to amaximum power throughput of the motive electrical power path. An exampleprocedure includes an operation to provide the contactor having acurrent rating that is higher than a current corresponding to a quickcharging power throughput of the motive electrical power path. Anexample procedure includes an operation to open the contactor is furtherin response to at least one of: a rate of change of the current flow; acomparison of the current flow to a threshold value; one of anintegrated or accumulated value of the current flow; and/or an expectedor predicted value of any of the foregoing.

Referencing FIG. 52, an example procedure includes an operation 5202 topower a motive electrical power path of a vehicle through a currentprotection circuit including a thermal fuse and a contactor in a seriesarrangement with the thermal fuse; an operation 5204 to determine acurrent flow through the motive electrical power path; an operation 5206to open the contactor in response to the current flow exceeding athreshold value; an operation 5208 to confirm that vehicle operatingconditions allow for a re-connection of the contactor; and an operation5210 to command the contactor to close in response to the vehicleoperating conditions. Previously known fused system, including systemshaving a controllable pyro-fuse, are not capable of restoring systempower after an overcurrent event, as the fuse has opened the circuit andcannot be restored. Certain example embodiments throughout the presentdisclosure provide for a system that can open the circuit withoutactivation of the fuse under certain circumstances. Accordingly, incertain embodiments, power can be restored after a high current event,providing for additional capability. However, in certain embodiments, itmay be undesirable to restore power to the system, for example if thesystem is being accessed by emergency personnel and/or service after theovercurrent event. In certain embodiments, the controller is configuredto perform certain checks, including checking current operatingconditions and permissions, before attempting to restore power.Additionally or alternatively, the controller is configured todetermine, during the attempted restoration of power and/or shortlythereafter, whether a condition causing an overcurrent event is stillpresent. Additionally or alternatively, the controller is configured todetermine whether the contactor or another electrical device has beendamaged during the overcurrent event, or during the disconnectionprocess being performed to halt the overcurrent event.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to confirm the vehicleoperating conditions, and in certain embodiments further includesdetermining at least one vehicle operating condition such as: anemergency vehicle operating condition; a user override vehicle operatingcondition; a service event vehicle operating condition; and are-connection command communicated on a vehicle network. In certainembodiments, an emergency vehicle operating condition may indicate thata reconnection is desirable—for example where continued operation of thevehicle is more important than damage to the electrical system of thevehicle. In certain embodiments, an emergency vehicle operatingcondition may indicate that a reconnection is undesirable—for examplewhere the vehicle has experienced an accident, and disconnection ofpower is desired to protect vehicle occupants and/or emergency responsepersonnel. In certain embodiments, a service event vehicle operatingcondition indicates that a reconnection is desirable—for example where aservicing operator is requesting re-powering of the vehicle. In certainembodiments, a service event vehicle operating condition indicates thata reconnection is undesirable—for example when service personnel areperforming service, maintenance, or repairs on the vehicle.

An example procedure includes an operation to monitor the motiveelectrical power path during the commanding the contactor to close, andre-opening the contactor in response to the monitoring (e.g., where thepost-closing current and/or a current transient indicates that acondition causing the overcurrent may still be active). An exampleprocedure includes an operation to determine an accumulated contactoropen event description in response to the opening the contactor, and/oran operation to prevent the commanding the contactor to close inresponse to the accumulated contactor open event description exceeding athreshold value. For example, the accumulated contactor open event maybe determined from a number of contactor open events under load, and/oraccording to a severity of those events. Where a number of open eventsunder load are experienced, and/or where one or more severe open eventsare experienced, re-connection of the contactor may be undesirable toavoid the risk of further damage, overheating of the contactor, and/orsticking or welding of a damaged contactor that may prevent a subsequentre-opening of the contactor. An example procedure includes an operationto adjust the accumulated contactor open event description in responseto the current flow during the opening of the contactor. An exampleprocedure includes an operation to diagnose a welded contactor inresponse to one of the current flow during the opening the contactor,and/or a monitoring of the motive electrical power path during thecommanding the contactor to close. An example procedure includes anoperation to diagnose a welded contactor in response to a monitoring ofat least one of a contactor actuator position (e.g., a failure of theactuator to respond as expected on command), a contactor actuatorresponse, and/or the motive electrical power path during the opening thecontactor. An example procedure further includes an operation to preventthe commanding the contactor to close in response to the diagnosedwelded contactor.

Referencing FIG. 53, an example apparatus includes a motive electricalpower current protection circuit 5308 structured to: determine a currentflow through a motive electrical power path 5304 of a vehicle; and opena contactor 5322 disposed in the current protection circuit 5308including a thermal fuse 5320 and the contactor 5322 in a seriesarrangement with the thermal fuse 5320 in response to the current flowexceeding a threshold value. The apparatus further includes a vehiclere-power circuit 5316 structured to: confirm that vehicle operatingconditions allow for a re-connection of the contactor; and to close thecontactor 5322 in response to the vehicle operating conditions.

Certain further aspects of an example apparatus are described following,any one or more of which may be present in certain embodiments. Anexample apparatus includes where the vehicle re-power circuit 5316 isfurther structured to confirm the vehicle operating conditions byconfirming at least one vehicle operating condition such as: anemergency vehicle operating condition; a user override vehicle operatingcondition; a service event vehicle operating condition; and are-connection command communicated on a vehicle network (not shown). Forexample, a system may include an operator override interface (e.g., abutton, a sequence of control inputs, or the like) that provide an inputfor the operator to request continued power operations where the motiveelectrical power current protection circuit 5308 has opened thecontactor 5322 to protect the motive power system. In certainembodiments, operator access to the override is utilized by the vehiclere-power circuit 5316 to command a re-connection of the contactor. Incertain embodiments, the re-connection by an operator input includesonly allowing a re-connection for certain applications (e.g., anemergency or military vehicle), and/or only allowing a re-connection fora period of time (e.g., 10 seconds or 30 seconds), and/or only allowinga re-connection when the electrical conditions after the re-connectiondo not indicate that another overcurrent event is occurring. In certainembodiments, the vehicle re-power circuit 5316 additionally oralternatively may de-rate maximum power, de-rate the maximum power slewrate, provide a notification or warning to the operator duringre-connection operations, and/or provide a notification or warning tothe operator when a re-connection time period is about to expire (e.g.,a first light or light sequence during re-connection operations, and adifferent light or light sequence when the re-connection time period isabout to expire).

An example apparatus includes where the motive electrical power currentprotection circuit 5308 is further structured to monitor the motiveelectrical power path during the closing the contactor to close, andwhere the vehicle re-power circuit 5316 is further structured to re-openthe contactor in response to the monitoring. An example apparatusincludes a contactor status circuit 5318 structured to determine anaccumulated contactor open event description in response to the openingthe contactor 5322; where the vehicle re-power circuit 5316 is furtherstructured to prevent the closing the contactor 5322 in response to theaccumulated contactor open event description exceeding a thresholdvalue; and/or where the contactor status circuit 5318 is furtherstructured to adjust the accumulated contactor open event description inresponse to the current flow during the opening the contactor. Anexample apparatus includes a contactor status circuit 5318 structured todiagnose a welded contactor in response to one of, during the commandingthe contactor to close: the current flow during the opening thecontactor 5322, and/or a monitoring of the motive electrical power pathby the motive electrical power current protection circuit 5308. Anexample apparatus includes a contactor status circuit 5318 structured todiagnose a welded contactor in response to a monitoring of, during theopening of the contactor, at least one of: a contactor actuator positionby the vehicle re-power circuit 5316; a contactor actuator response bythe vehicle re-power circuit 5316; and the motive electrical power pathby the motive electrical power current protection circuit 5308; and/orwhere the contactor status circuit 5318 is further structured to preventthe closing the contactor in response to the diagnosed welded contactor.

An example system (e.g., referencing FIGS. 1 and 2) includes a vehiclehaving a motive electrical power path; a power distribution unitincluding: a current protection circuit disposed in the motiveelectrical power path, the current protection circuit including athermal fuse and a contactor in a series arrangement with the thermalfuse; a high voltage power input coupling including a first electricalinterface for a high voltage power source; a high voltage power outputcoupling including a second electrical interface for a motive powerload; and where the current protection circuit electrically couples thehigh voltage power input to the high voltage power output, and where thecurrent protection circuit is at least partially disposed in a laminatedlayer (e.g., referencing FIGS. 12 through 17) of the power distributionunit, where the laminated layer includes an electrically conductive flowpath disposed between two electrically insulating layers.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where current protection circuit includes amotive power bus bar disposed in the laminated layer of the powerdistribution unit. An example system includes where the vehicle furtherincludes an auxiliary electrical power path; where the powerdistribution unit further includes: an auxiliary current protectioncircuit disposed in the auxiliary electrical power path, the auxiliarycurrent protection circuit including a second thermal fuse; an auxiliaryvoltage power input coupling including a first auxiliary electricalinterface for a low voltage power source; an auxiliary voltage poweroutput coupling including a second auxiliary electrical interface for aan auxiliary load; and where the auxiliary current protection circuitelectrically couples the auxiliary voltage power input to the auxiliaryvoltage power output, and where the auxiliary current protection circuitis at least partially disposed in the laminated layer of the powerdistribution unit. An example system includes where the laminated layerof the power distribution unit further includes at least one thermallyconductive flow path disposed between two thermally insulating layers;where the at least one thermally conductive flow path is configured toprovide thermal coupling between a heat sink (e.g., a cooling system, ahousing or other system aspect having a high thermal mass, and/orambient air), and a heat source, where the heat source includes at leastone of the contactor, the thermal fuse, and the second thermal fuse;where the heat sink includes at least one of a thermal coupling to anactive cooling source and a housing of the power distribution unit;and/or further including a thermal conduit disposed between the at leastone thermally conductive flow path and the heat source.

Referencing FIG. 55, an example system includes a vehicle 5502 having amotive electrical power path 5504; a power distribution unit 5506including a current protection circuit 5508 disposed in the motiveelectrical power path 5504, the current protection circuit 5508including a thermal fuse 5520 and a contactor 5522 in a seriesarrangement with the thermal fuse 5520; a current source circuit 5516electrically coupled to the thermal fuse 5520 and structured to inject acurrent across the thermal fuse 5520 (e.g., using an op-amp drivencurrent source); and a voltage determination circuit 5518 electricallycoupled to the thermal fuse 5520 and structured to determine at leastone of an injected voltage amount and a thermal fuse impedance value.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the motive electrical power path 5504includes a direct current power path (e.g., the motive power path);where the current source circuit 5516 includes at least one of analternating current source and a time varying current source, andfurther including a hardware filter 5524 electrically coupled to thethermal fuse 5520. In the example, the hardware filter 5524 isconfigured in response to an injection frequency of the current sourcecircuit 5516; where the hardware filter 5524 includes a high pass filter5526 having a cutoff frequency determined in response to the injectionfrequency of the current source circuit 5516 (e.g., to remove voltagefluctuations that are significantly lower than the injection ACfrequency). An example system includes the hardware filter 5524 having alow pass filter 5528 having a cutoff frequency determined in response toat least one of the injection frequency of the current source circuit(e.g., to remove voltage fluctuations induced by the current injection)or a load change value of the motive electrical power path 5504 (e.g.,to remove transient fluctuations caused by a change in the load). Incertain embodiments, the high pass filtered voltage is analyzedseparately from the low pass filtered voltage—e.g., where the basevoltage signal is analyzed separately with a low pass filter applied andwith a high pass filter applied, allowing for a separate determinationof the response voltage to the injected current, and of the base voltagedue to the current load. In certain embodiments, the voltagedetermination circuit 5518 is further structured to determine todetermine an injected voltage drop of the thermal fuse in response to anoutput of the high pass filter; and/or where the voltage determinationcircuit 5518 is further structured to determine the thermal fuseimpedance value in response to the injected voltage drop. In certainembodiments, the voltage determination circuit 5518 is furtherstructured to determine a load voltage drop of the thermal fuse 5520 inresponse to an output of the low pass filter, and/or where the systemfurther includes a load current circuit 5519 structured to determine aload current through the fuse in response to the thermal fuse impedancevalue (e.g., determined from the response voltage to the injectedcurrent), and further in response to the load voltage drop from the lowpass filter.

Referencing FIG. 54, an example system includes a vehicle 5402 having amotive electrical power path 5404; a power distribution unit 5406including a current protection circuit 5408 disposed in the motiveelectrical power path 5404, the current protection circuit 5408including a thermal fuse 5420 and a contactor 5422 in a seriesarrangement with the thermal fuse 5420. The example system furtherincludes a current source circuit 5416 electrically coupled to thethermal fuse 5420 and structured to inject a current across the thermalfuse 5420; and a voltage determination circuit 5518 electrically coupledto the thermal fuse 5420 and structured to determine at least one of aninjected voltage amount and a thermal fuse impedance value, where thevoltage determination circuit 5518 includes a high pass filter (e.g.,analog filter 5428, depicted in a bandpass filter 5426, but which mayadditionally or alternatively include a high pass filter) having acutoff frequency selected in response to a frequency of the injectedcurrent.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the voltage determination circuit 5518further includes a bandpass filter 5426 having a bandwidth selected tobound the frequency of the injected current. For example, where thefrequency of the injected current is 200 Hz, the bandpass filter 5426may be configured with cutoff frequencies of 190 Hz to 210 Hz, 195 Hz to205 Hz, 199 Hz to 201 Hz, within 5% of the injected frequency, and/orwithin 1% of the injected frequency. One of skill in the art, having thebenefit of the disclosures herein, can determine an appropriateinjection frequency and/or range of injection frequencies to beutilized, and values for the high pass filter and/or the band passfilter to provide an appropriately conditioned voltage responsedetermination to the injected current. Certain considerations forselecting an injected frequency and the band pass filter range include,without limitation, frequency components in electrical communicationwith the motive electrical power system including base frequencies andharmonics, the noise environment of the system, the desired accuracy ofthe thermal fuse impedance value determination, the dynamic response andcapability of the current injector, the dynamic response and attenuationcapability of the filters, the time available for performing aninjection event, a number of fuses coupled to the current injector(s)that are to be checked, the desired time response for determiningchanges in the fuse impedance value, and/or the amount of statisticaland/or frequency component analysis post-processing that is available onthe controller 5414.

An example system includes where the high pass filter includes an analoghardware filter 5428, and where the bandpass filter 5426 includes adigital filter 5430. For example, the analog hardware filter 5428 mayperform the high pass filtering function, and a downstream digitalfilter 5430 may perform a digital or analytical bandpass filteringfunction on the high pass filtered input. An example system includeswhere the high pass filter and the bandpass filter are both digitalfilters 5430. An example voltage determination circuit 5518 is furtherstructured to determine the thermal fuse impedance value in response tothe injected voltage drop from the high pass and band pass filteredinput. An example system includes a fuse characterization circuit 5418that stores a fuse resistance value and/or a fuse impedance value,and/or the fuse characterization circuit 5418 further updates the storedone of the fuse resistance value and the fuse impedance value inresponse to the thermal fuse impedance value. An example system includeswhere the fuse characterization circuit 5418 is further updates thestored one of the fuse resistance value and the fuse impedance value byperforming at least one operation such as: updating a value to thethermal fuse impedance value (e.g., instantaneously or periodicallyreplacing the stored value with the determined value); filtering a valueusing the thermal fuse impedance value as a filter input (e.g., movingcontinuously toward the determined value, such as with a selected timeconstant); rejecting the thermal fuse impedance value for a period oftime or for a number of determinations of the thermal fuse impedancevalue (e.g., where a low trust and/or anomalous value is determined,setting the value aside or ignoring it for a period of time or selectednumber of determinations, and/or later confirming the value if itappears to be consistent over time); and/or updating a value byperforming a rolling average of a plurality of thermal impedance valuesover time (e.g., utilizing a rolling buffer or other memory construct toreplace older determinations with updated determinations). An examplesystem includes where the power distribution unit 5406 further includesa number of thermal fuses 5420 disposed therein, and where the currentsource circuit 5416 is further electrically coupled to the number ofthermal fuses (which maybe a single current source selectively coupledto various fuses, and/or separate current sources controllable by thecurrent source circuit 5416). the example current source circuit 5416further configured to sequentially inject a current across each of thenumber of thermal fuses (e.g., to check the thermal fuse impedance valueand/or resistance for each of the fuses in a selected sequence). Anexample voltage determination circuit 5518 is further electricallycoupled to each of the number of thermal fuses, and further structuredto determine at least one of an injected voltage amount a thermal fuseimpedance value for each of the number of thermal fuses. An examplecurrent source circuit 5416 is further configured to sequentially injectthe current across each of the number of thermal fuses in a selectedorder of the fuses (e.g., the fuses need not be checked in anyparticular order, and need not be checked with the same frequency or thesame number of times). An example current source circuit 5416 furtherstructured adjusts the selected order in response to at least one of: arate of change of a temperature of each of the fuses (e.g., a fuse thatis changing temperature more quickly may be checked more frequently); animportance value of each of the fuses (e.g., a motive power fuse may bechecked more frequently than a non-critical accessory fuse); acriticality of each of the fuses (e.g., a mission disabling fuse may bechecked more frequently than another fuse); a power throughput of eachof the fuses (e.g., similar to the rate of change of temperature, and/orindicative of the potential for increased wear or aging of the fuse);and/or one of a fault condition or a fuse health condition of each ofthe fuses (e.g., a fuse having a suspected or active fault, and/or afuse that is worn or aged, may be checked more frequently to track theprogress of the fuse, confirm or clear the diagnostic, and/or to morerapidly detect or respond to a failure). An example current sourcecircuit 5416 is further structured to adjust the selected order inresponse to one of a planned duty cycle and an observed duty cycle ofthe vehicle (e.g., adjusting the fuse checking order and/or frequencybased on the planned duty cycle of the vehicle or the motive powercircuit, and/or based on the observed duty cycle of the vehicle or themotive power circuit, allowing adjustment for various applicationsand/or observed run-time changes). An example system includes where thecurrent source circuit 5416 is further structured to sweep the injectedcurrent through a range of injection frequencies (e.g., ensuringrobustness to system noise, informing a multi-frequency impedance modelof the fuse, and/or passively or actively avoiding injected noise ontothe power circuit including the fuse). An example current source circuit5416 is further structured to inject the current across the thermal fuseat a number of injection frequencies (e.g., similar to a sweep, butusing a selected number of discrete frequencies, which achieves some ofthe benefits of the sweep with more convenient filtering and processing,and includes updating the selected injection frequencies based on systemchanges such as loads, observed noise, and/or observed value of selectedfrequencies in characterizing the fuse). An example system includeswhere the current source circuit 5416 is further structured to injectthe current across the thermal fuse at a number of injection voltageamplitudes. The injection voltage amplitude may be coupled with theinjection current amplitude. Wherever an injection amplitude isdescribed throughout the present disclosure, it is understood that aninjection amplitude may be a current injection amplitude and/or avoltage injection amplitude, and in certain operating conditions thesemay be combined (e.g., selecting a voltage amplitude until a currentlimit in the current source is reached, selecting a current amplitudeuntil a voltage limit in the current source is reached, and/or followingan amplitude trajectory that may include a combination of voltage and/orcurrent). An example system includes where the current source circuit5416 is further structured to inject the current across the thermal fuseat an injection voltage amplitude determined in response to a powerthroughput of the thermal fuse (e.g., injecting a greater amplitude athigh load to assist a signal-to-noise ratio, and/or a lower amplitude athigh load to reduce the load on the fuse). An example system includeswhere the current source circuit 5416 is further structured to injectthe current across the thermal fuse at an injection voltage amplitudedetermined in response to a duty cycle of the vehicle.

Referencing FIG. 56, an example procedure includes an operation 5602 todetermine null offset voltage for a fuse current measurement system,including an operation 5604 to determine that no current is demanded fora fuse load for a fuse electrically disposed between an electrical powersource and an electrical load; and the operation 5604 includingdetermining a null offset voltage in response to the no current demandedfor the fuse load; and an operation 5606 to store the null offsetvoltage.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to update a stored nulloffset voltage in response to the determined null offset voltage. Anexample procedure includes an operation to diagnose a component inresponse to the null offset voltage, for example where a high nulloffset voltage indicates that a component in the system may not beoperating properly. An example procedure includes an operation todetermine which one of a plurality of components is contributing to thenull offset voltage (e.g., by performing a null offset voltagedetermination with selected components coupled or de-coupled from thecircuit having the fuse being checked). An example procedure includes anoperation to determine that no current is demanded for the fuse load byperforming at least one operation such as: determining that a key-offevent has occurred for a vehicle including the fuse, the electricalpower source, and the electrical load; determining that a key-on eventhas occurred for the vehicle; determining that the vehicle is poweringdown; and/or determining that the vehicle is in an accessory condition,where the vehicle in the accessory condition does not provide powerthrough the fuse (e.g., a keyswitch accessory position for anapplication where the motive power fuse is not energized in theaccessory position).

Referencing FIG. 57, an example apparatus to determine offset voltage toadjust a fuse current determination includes a controller 5702 having afuse load circuit 5708 structured to determine that no current isdemanded for a fuse load, and to further determine that contactorsassociated with the fuse are open; an offset voltage determinationcircuit 5722 structured to determine an offset voltage corresponding toat least one component in a fuse circuit associated with the fuse, inresponse to the determining that no current is demanded for the fuseload; and an offset data management circuit 5724 structured to store theoffset voltage, and to communicate a current calculation offset voltagefor use by a controller to determine current flow through the fuse.

Referencing FIG. 58, an example procedure includes an operation 5802 toprovide digital filters for a fuse circuit in a power distribution unit,including an operation 5804 to inject an alternating current across afuse, where the fuse is electrically disposed between an electricalpower source and an electrical load; an operation 5806 to determine thebase power through a fuse by performing a low-pass filter operation onone of a measured current value and a measured voltage value for thefuse; and an operation 5808 to determine an injected current value byperforming a high-pass filter operation on one of the measured currentvalue and the measured voltage value for the fuse.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to adjust parameters ofat least one of the low-pass filter and the high-pass filter in responseto a duty cycle of one of power and current through the fuse. An exampleprocedure includes an operation to sweep the injected alternatingcurrent through a range of injection frequencies. An example procedureincludes an operation to inject the alternating current across the fuseat a number of injection frequencies. An example procedure includes anoperation where the current source circuit is further structured toinject the current across the fuse at a number of injection voltageamplitudes. An example procedure includes an operation where the currentsource circuit is further structured to inject the current across thefuse at an injection voltage amplitude determined in response to a powerthroughput of the fuse. In certain embodiments, the low-pass filterand/or the high-pass filter are digital filters, and where the adjustingparameters of the digital filters includes adjusting values for thedigital filter(s). An example procedure includes further processing themeasured voltage value with a digital bandpass filter after performingthe high-pass filter, and determining a fuse resistance, fuse dynamicresistance, and/or fuse impedance value based on the high-pass and thenbandpass filtered measured voltage value.

Referencing FIG. 59, an example procedure includes an operation 5902 tocalibrate a fuse resistance determination algorithm, including: anoperation 5904 to store a number of calibration sets corresponding to anumber of duty cycle values, the duty cycles including an electricalthroughput value corresponding to a fuse electrically disposed betweenan electrical power source and an electrical load. Example calibrationsets include current source injection settings for a current injectiondevice operationally coupled to the fuse, including injectionfrequencies, injection duty cycles (e.g., on-time for each cycle),injection waveform shapes, fuse sequence operations (e.g., the order andfrequency to check each fuse), injection amplitudes, and/or injectionrun-times (e.g., the number of seconds or milliseconds for eachinjection sequence for each fuse, such as 130 ms, 20 ms, 1 second,etc.). The example procedure includes an operation 5908 to determine aduty cycle of a system including the fuse, the electrical power source,and the electrical load; an operation 5910 to determine injectionsettings for the current injection device in response to the number ofcalibration sets and the determined duty cycle (e.g., using theindicated calibration set according to the determined duty cycle, and/orinterpolating between calibration sets); and an operation 5912 tooperate the current injection device in response to the determinedinjection settings.

An example procedure further includes an operation where the calibrationsets further comprise filter settings for at least one digital filter,where the method further includes determining the fuse resistanceutilizing the at least one digital filter.

Referencing FIG. 60, an example procedure includes an operation 6002 toprovide unique current waveforms to improve fuse resistance measurementfor a power distribution unit. In certain embodiments, the procedureincludes an operation 6004 to confirm that contactors electricallypositioned in a fuse circuit are open, where the fuse circuit includes afuse electrically disposed between an electrical power source and anelectrical load, and/or an operation 6006 to determine a null voltageoffset value for the fuse circuit. An example procedure includes anoperation 6006 to conduct a number of current injection sequences acrossthe fuse, where each of the current injection sequences includes aselected current amplitude, current frequency, and current waveformvalue. An example procedure further includes an operation 6010 todetermine a fuse resistance value in response to the current injectionsequences and/or the null voltage offset value.

Certain further aspects of an example procedure are described following,any one or more of which may be present in certain embodiments. Anexample procedure further includes an operation to adjust filteringcharacteristics for a digital filter in response to each of the numberof current injection sequences, and to measure one of the fuse circuitvoltage or the fuse circuit current with the digital filter during thecorresponding current injection sequence using the adjusted filteringcharacteristics.

Referencing FIG. 61, an example system includes a vehicle 6102 having amotive electrical power path 6104; a power distribution unit including acurrent protection circuit 6108 disposed in the motive electrical powerpath 6104, where the current protection circuit 6108 includes a thermalfuse 6120 and a contactor 6122 in a series arrangement with the thermalfuse 6120. The example system includes a controller 6114 having acurrent source circuit 6116 electrically coupled to the thermal fuse6120 and structured to inject a current across the thermal fuse 6120,and a voltage determination circuit 6118 electrically coupled to thethermal fuse 6120 and structured to determine an injected voltage amountand a thermal fuse impedance value. The example voltage determinationcircuit 6118 is structured to perform a frequency analysis operation todetermine the injected voltage amount. Example and non-limitingfrequency analysis operations include applying analog and/or digitalfilters to remove frequency components of the fuse voltage that are notof interest and/or that are not related to the injected frequency.Example and non-limiting frequency analysis operations include utilizingat least one frequency analysis technique selected from the techniquessuch as: a Fourier transform, a fast Fourier transform, a Laplacetransform, a Z transform, and/or a wavelet analysis. In certainembodiments, a frequency analysis operation is performed on filteredand/or unfiltered measurements of the thermal fuse voltage.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the voltage determination circuit 6118further structured to determine the injected voltage amount bydetermining an amplitude of a voltage across the fuse at a frequency ofinterest; and/or where the frequency of interest is determined inresponse to a frequency of the injected voltage. An example systemincludes where the current source circuit 6116 is further structured tosweep the injected current through a range of injection frequencies. Anexample system includes where the current source circuit 6116 is furtherstructured to inject the current across the thermal fuse 6120 at anumber of injection frequencies. An example system includes where thecurrent source circuit 6116 is further structured to inject the currentacross the thermal fuse 6120 at a number of injection voltageamplitudes. An example system includes where the current source circuit6116 is further structured to inject the current across the thermal fuse6120 at an injection voltage amplitude determined in response to a powerthroughput of the thermal fuse 6120. An example system includes wherethe current source circuit 6116 is further structured to inject thecurrent across the thermal fuse 6120 at an injection voltage amplitudedetermined in response to a duty cycle of the vehicle 6102.

Referencing FIG. 62, an example system includes a vehicle 6202 having amotive electrical power path 6204; a power distribution unit including acurrent protection circuit 6208 disposed in the motive electrical powerpath 6204, the current protection circuit 6208 including a thermal fuse6220 and a contactor 6222 in a series arrangement with the thermal fuse.The example system further includes a controller 6214 having a currentsource circuit 6216 electrically coupled to the thermal fuse andstructured to determine that a load power throughput of the motiveelectrical power path 6204 is low, and to inject a current across thethermal fuse 6220 in response to the load power throughput of the motiveelectrical power path 6204 being low. The controller 6214 furtherincludes a voltage determination circuit 6218 electrically coupled tothe thermal fuse 6220 and structured to determine at least one of aninjected voltage amount and a thermal fuse impedance value, and wherethe voltage determination circuit 6218 includes a high pass filterhaving a cutoff frequency selected in response to a frequency of theinjected current.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the current source circuit 6216 is furtherstructured to determine the load power throughput of the motiveelectrical power path 6204 is low in response to the vehicle being in ashutdown state. An example system includes where the current sourcecircuit 6216 is further structured to determine the load powerthroughput of the motive electrical power path 6204 is low in responseto the vehicle being in a keyoff state. An example system includes wherethe current source circuit 6216 is further structured to determine theload power throughput of the motive electrical power path 6204 is low inresponse to a motive torque request for the vehicle being zero. Anexample system includes where the power distribution unit furtherincludes a number of fuses, and where the current source circuit 6216 isfurther structured to inject the current across each of the fuses in aselected sequence; and/or where the current source circuit 6216 isfurther structured to inject the current across a first one of theplurality of fuses at a first shutdown event of the vehicle, and toinject the current across a second one of the plurality of fuses at asecond shutdown event of the vehicle (e.g., to limit run-time of thecontroller 6214 during shutdown events that may be of limited duration,an example current source circuit 6216 checks only one or a subset ofthe fuses during a given shutdown event, only checking all of the fusesover a number of shutdown events).

Referencing FIG. 62, an example system includes a vehicle 6202 having amotive electrical power path 6204; a power distribution unit including acurrent protection circuit 6308 disposed in the motive electrical powerpath 6204, where the current protection circuit 6208 includes a thermalfuse 6220 and a contactor 6222 in a series arrangement with the thermalfuse 6220. An example system further includes a controller 6214 having acurrent source circuit 6218 electrically coupled to the thermal fuse6220 and structured to inject a current across the thermal fuse 6220;and a voltage determination circuit 6218 electrically coupled to thethermal fuse 6220 and structured to determine at least one of aninjected voltage amount and a thermal fuse impedance value. The examplevoltage determination circuit 6218 includes a high pass filter having acutoff frequency selected in response to a frequency of the injectedcurrent. The example controller 6214 further includes a fuse statuscircuit 6219 structured to determine a fuse condition value in responseto the at least one of the injected voltage amount and the thermal fuseimpedance value. For example, a correlation between the fuse resistance(and/or dynamic resistance or impedance) may be established for aparticular fuse or type of fuse, and the example fuse status circuit6219 determines the fuse condition value in response to the observedfuse resistance or other related parameter. In certain embodiments, thefuse status circuit 6219 may additionally include other information,such as the power throughput accumulated through the fuse, powertransient events accumulated and/or power excursion events accumulatedthrough the fuse, temperature events and/or temperature transientsaccumulated by the fuse, and/or an operational longevity parameter suchas hours of operation, miles of operation, hours of powered operation,or the like.

Certain further aspects of an example system are described following,any one or more of which may be present in certain embodiments. Anexample system includes where the fuse status circuit 6219 is furtherstructured to provide the fuse condition value by providing at least oneof a fault code or a notification of the fuse condition value (e.g.,storing a parameter, communicating a fault parameter to a datalink,and/or providing a fault parameter to a service tool). An example fusestatus circuit 6219 further adjusts a maximum power rating for themotive electrical power path 6204, a maximum power slew rate for themotive electrical power path; and/or adjusts a configuration of thecurrent protection circuit in response to the fuse condition value(e.g., sharing a load between parallel fuses, bypassing the fuse atlower thresholds for power or power transients, etc.). An example powerdistribution unit further includes an active cooling interface 6224, andwhere the fuse status circuit 6219 further adjusts the active coolinginterface 6224 in response to the fuse condition value (e.g., providingadditional cooling for an aging fuse, and/or lowering a threshold for anactive cooling increase request for an aging fuse). An example fusestatus circuit 6219 is further structured to clear the at least one ofthe fault code or the notification of the fuse condition value inresponse to the fuse condition value indicating that the fuse conditionhas improved (e.g., where a previous indication from the fuse conditionvalue indicated degradation, but continued observations indicate thatdegradation of the fuse is not present; upon a reset by an operator or aservice technician, such as an indication that the fuse has been checkedor changed, etc.). An example fuse status circuit 6219 is furtherstructured to clear the at least one of the fault code or thenotification of the fuse condition value in response to a service eventfor the fuse (e.g., through a service tool, planned sequence of inputs,or the like); where the fuse status circuit 6219 is further structuredto determine a fuse life remaining value in response to the fusecondition value (e.g., through a correlation of the fuse condition valueto the fuse life remaining value, and/or using a cutoff or thresholdvalue of the fuse condition value to trigger an end-of-life condition orwarning; for example it may be determined that a particular value of thefuse condition value indicates that the fuse is at 90% of a plannedlife, has 500 hours of operation remaining, etc.); where the fuse statuscircuit 6219 is further structured to determine the fuse life remainingvalue further in response to a duty cycle of the vehicle (e.g., incertain embodiments a heavier vehicle duty cycle will consume theremaining fuse life more quickly, which may be accounted for indetermining the fuse life remaining value, and which may depend upon theunits of fuse life remaining such as operating hours versus calendardays, and/or upon the notification type—e.g., a service light, aquantitative time remaining, etc.—to a service technician, operator, orthe like); and/or where the fuse status circuit 6219 is furtherstructured to determine the fuse life remaining value further inresponse to one of: an adjusted maximum power rating for the motiveelectrical power path, an adjusted maximum power slew rate for themotive electrical power path, and/or an adjusted configuration of thecurrent protection circuit (e.g., where the fuse status circuit 6219 hasadjusted system parameters such as power throughput, fuse loading and/orbypass configurations or thresholds, and/or cooling strategies, the fusestatus circuit 6219 may account for the estimated life extension of thefuse due to these or any other mitigating strategies in place).

Referencing FIG. 63, an example system includes a vehicle 6302 having amotive electrical power path 6304; a power distribution unit including acurrent protection circuit 6308 disposed in the motive electrical powerpath 6304, where the current protection circuit further includes athermal fuse 6320 and a contactor 6322 in a series arrangement with thethermal fuse 6320. The example system further includes a controller 6314having a fuse thermal model circuit 6316 structured to determine a fusetemperature value of the thermal fuse 6320, and to determine a fusecondition value in response to the fuse temperature value. An examplesystem includes a current source circuit 6318 electrically coupled tothe thermal fuse 6320 and structured to inject a current across thethermal fuse 6320; a voltage determination circuit 6319 electricallycoupled to the thermal fuse 6320 and structured to determine at leastone of an injected voltage amount and a thermal fuse impedance value,and where the voltage determination circuit 6319 includes a high passfilter having a cutoff frequency selected in response to a frequency ofthe injected current. An example fuse thermal model circuit 6316 furtherdetermines the fuse temperature value of the thermal fuse further inresponse to the at least one of the injected voltage amount and thethermal fuse impedance value. An example system includes where the fusethermal model circuit 6316 is further structured to determine the fusecondition value by counting a number of thermal fuse temperatureexcursion events. Example thermal fuse temperature excursion eventsinclude: a temperature rise threshold value within a time thresholdvalue, a temperature of the thermal fuse exceeding a threshold value,and/or more than one threshold of these (e.g., counting more severeoccurrences as more than one temperature excursion event). An examplesystem includes the fuse thermal model circuit is further determiningthe fuse condition value by integrating the fuse temperature value,integrating a temperature based index (e.g., based on temperaturesand/or temperature change rates), and/or integrating the fusetemperature value for temperatures above a temperature threshold.

The programmed methods and/or instructions described herein may bedeployed in part or in whole through a machine that executes computersoftware, program codes, and/or instructions on a processor orprocessors. “Processor” used herein is synonymous with the plural“processors” and the two terms may be used interchangeably unlesscontext clearly indicates otherwise. The processor may be part of aserver, client, network infrastructure, mobile computing platform,stationary computing platform, or other computing platform. A processormay be any kind of computational or processing device capable ofexecuting program instructions, codes, binary instructions and the like.The processor may be or include a signal processor, digital processor,embedded processor, microprocessor or any variant such as a co-processor(math co-processor, graphic co-processor, communication co-processor andthe like) and the like that may directly or indirectly facilitateexecution of program code or program instructions stored thereon. Inaddition, the processor may enable execution of multiple programs,threads, and codes. The threads may be executed simultaneously toenhance the performance of the processor and to facilitate simultaneousoperations of the application. By way of implementation, methods,program codes, program instructions and the like described herein may beimplemented in one or more thread. The thread may spawn other threadsthat may have assigned priorities associated with them; the processormay execute these threads based on priority or any other order based oninstructions provided in the program code. The processor may includememory that stores methods, codes, instructions and programs asdescribed herein and elsewhere. The processor may access a storagemedium through an interface that may store methods, codes, andinstructions as described herein and elsewhere. The storage mediumassociated with the processor for storing methods, programs, codes,program instructions or other type of instructions capable of beingexecuted by the computing or processing device may include but may notbe limited to one or more of a CD-ROM, DVD, memory, hard disk, flashdrive, RAM, ROM, cache and the like.

A processor may include one or more cores that may enhance speed andperformance of a multiprocessor. In embodiments, the process may be adual core processor, quad core processors, other chip-levelmultiprocessor and the like that combine two or more independent cores(called a die).

The methods and systems described herein may be deployed in part or inwhole through a machine that executes computer software on a server,client, firewall, gateway, hub, router, or other such computer and/ornetworking hardware. The software program may be associated with aserver that may include a file server, print server, domain server,Internet server, intranet server and other variants such as secondaryserver, host server, distributed server and the like. The server mayinclude one or more of memories, processors, computer readable media,storage media, ports (physical and virtual), communication devices, andinterfaces capable of accessing other servers, clients, machines, anddevices through a wired or a wireless medium, and the like. The methods,programs or codes as described herein and elsewhere may be executed bythe server. In addition, other devices required for execution of methodsas described in this application may be considered as a part of theinfrastructure associated with the server.

The server may provide an interface to other devices including, withoutlimitation, clients, other servers, printers, database servers, printservers, file servers, communication servers, distributed servers andthe like. Additionally, this coupling and/or connection may facilitateremote execution of program across the network. The networking of someor all of these devices may facilitate parallel processing of a programor method at one or more location without deviating from the scope. Inaddition, any of the devices attached to the server through an interfacemay include at least one storage medium capable of storing methods,programs, code and/or instructions. A central repository may provideprogram instructions to be executed on different devices. In thisimplementation, the remote repository may act as a storage medium forprogram code, instructions, and programs.

The software program may be associated with a client that may include afile client, print client, domain client, Internet client, intranetclient and other variants such as secondary client, host client,distributed client and the like. The client may include one or more ofmemories, processors, computer readable media, storage media, ports(physical and virtual), communication devices, and interfaces capable ofaccessing other clients, servers, machines, and devices through a wiredor a wireless medium, and the like. The methods, programs or codes asdescribed herein and elsewhere may be executed by the client. Inaddition, other devices required for execution of methods as describedin this application may be considered as a part of the infrastructureassociated with the client.

The client may provide an interface to other devices including, withoutlimitation, servers, other clients, printers, database servers, printservers, file servers, communication servers, distributed servers andthe like. Additionally, this coupling and/or connection may facilitateremote execution of program across the network. The networking of someor all of these devices may facilitate parallel processing of a programor method at one or more location without deviating from the scope. Inaddition, any of the devices attached to the client through an interfacemay include at least one storage medium capable of storing methods,programs, applications, code and/or instructions. A central repositorymay provide program instructions to be executed on different devices. Inthis implementation, the remote repository may act as a storage mediumfor program code, instructions, and programs.

The methods and systems described herein may be deployed in part or inwhole through network infrastructures. The network infrastructure mayinclude elements such as computing devices, servers, routers, hubs,firewalls, clients, personal computers, communication devices, routingdevices and other active and passive devices, modules and/or componentsas known in the art. The computing and/or non-computing device(s)associated with the network infrastructure may include, apart from othercomponents, a storage medium such as flash memory, buffer, stack, RAM,ROM and the like. The processes, methods, program codes, instructionsdescribed herein and elsewhere may be executed by one or more of thenetwork infrastructural elements.

The methods, program codes, and instructions described herein andelsewhere may be implemented on a cellular network having multiplecells. The cellular network may either be frequency division multipleaccess (FDMA) network or code division multiple access (CDMA) network.The cellular network may include mobile devices, cell sites, basestations, repeaters, antennas, towers, and the like. The cell networkmay be a GSM, GPRS, 3G, 4G, LTE, EVDO, mesh, or other networks types.

The methods, programs codes, and instructions described herein andelsewhere may be implemented on or through mobile devices. The mobiledevices may include navigation devices, cell phones, mobile phones,mobile personal digital assistants, laptops, palmtops, netbooks, pagers,electronic books readers, music players and the like. These devices mayinclude, apart from other components, a storage medium such as a flashmemory, buffer, RAM, ROM and one or more computing devices. Thecomputing devices associated with mobile devices may be enabled toexecute program codes, methods, and instructions stored thereon.Alternatively, the mobile devices may be configured to executeinstructions in collaboration with other devices. The mobile devices maycommunicate with base stations interfaced with servers and configured toexecute program codes. The mobile devices may communicate on a peer topeer network, mesh network, or other communications network. The programcode may be stored on the storage medium associated with the server andexecuted by a computing device embedded within the server. The basestation may include a computing device and a storage medium. The storagedevice may store program codes and instructions executed by thecomputing devices associated with the base station.

The computer software, program codes, and/or instructions may be storedand/or accessed on machine readable media that may include: computercomponents, devices, and recording media that retain digital data usedfor computing for some interval of time; semiconductor storage known asrandom access memory (RAM); mass storage typically for more permanentstorage, such as optical discs, forms of magnetic storage like harddisks, tapes, drums, cards and other types; processor registers, cachememory, volatile memory, non-volatile memory; optical storage such asCD, DVD; removable media such as flash memory (e.g. USB sticks or keys),floppy disks, magnetic tape, paper tape, punch cards, standalone RAMdisks, Zip drives, removable mass storage, off-line, and the like; othercomputer memory such as dynamic memory, static memory, read/writestorage, mutable storage, read only, random access, sequential access,location addressable, file addressable, content addressable, networkattached storage, storage area network, bar codes, magnetic ink, and thelike.

The methods and systems described herein may transform physical and/oror intangible items from one state to another. The methods and systemsdescribed herein may also transform data representing physical and/orintangible items from one state to another.

The elements described and depicted herein, including in flow charts andblock diagrams throughout the figures, imply logical boundaries betweenthe elements. However, according to software or hardware engineeringpractices, the depicted elements and the functions thereof may beimplemented on machines through computer executable media having aprocessor capable of executing program instructions stored thereon as amonolithic software structure, as standalone software modules, or asmodules that employ external routines, code, services, and so forth, orany combination of these, and all such implementations may be within thescope of the present disclosure. Examples of such machines may include,but may not be limited to, personal digital assistants, laptops,personal computers, mobile phones, other handheld computing devices,medical equipment, wired or wireless communication devices, transducers,chips, calculators, satellites, tablet PCs, electronic books, gadgets,electronic devices, devices having artificial intelligence, computingdevices, networking equipment, servers, routers and the like.Furthermore, the elements depicted in the flow chart and block diagramsor any other logical component may be implemented on a machine capableof executing program instructions. Thus, while the foregoing drawingsand descriptions set forth functional aspects of the disclosed systems,no particular arrangement of software for implementing these functionalaspects should be inferred from these descriptions unless explicitlystated or otherwise clear from the context. Similarly, it may beappreciated that the various steps identified and described above may bevaried, and that the order of steps may be adapted to particularapplications of the techniques disclosed herein. All such variations andmodifications are intended to fall within the scope of this disclosure.As such, the depiction and/or description of an order for various stepsshould not be understood to require a particular order of execution forthose steps, unless required by a particular application, or explicitlystated or otherwise clear from the context.

The methods and/or processes described above, and steps thereof, may berealized in hardware, software or any combination of hardware andsoftware suitable for a particular application. The hardware may includea general-purpose computer and/or dedicated computing device or specificcomputing device or particular aspect or component of a specificcomputing device. The processes may be realized in one or moremicroprocessors, microcontrollers, embedded microcontrollers,programmable digital signal processors or other programmable device,along with internal and/or external memory. The processes may also, orinstead, be embodied in an application specific integrated circuit, aprogrammable gate array, programmable array logic, or any other deviceor combination of devices that may be configured to process electronicsignals. It may further be appreciated that one or more of the processesmay be realized as a computer executable code capable of being executedon a machine-readable medium.

The computer executable code may be created using a structuredprogramming language such as C, an object oriented programming languagesuch as C++, or any other high-level or low-level programming language(including assembly languages, hardware description languages, anddatabase programming languages and technologies) that may be stored,compiled or interpreted to run on one of the above devices, as well asheterogeneous combinations of processors, processor architectures, orcombinations of different hardware and software, or any other machinecapable of executing program instructions.

Thus, in one aspect, each method described above and combinationsthereof may be embodied in computer executable code that, when executingon one or more computing devices, performs the steps thereof. In anotheraspect, the methods may be embodied in systems that perform the stepsthereof, and may be distributed across devices in a number of ways, orall of the functionality may be integrated into a dedicated, standalonedevice or other hardware. In another aspect, the means for performingthe steps associated with the processes described above may include anyof the hardware and/or software described above. All such permutationsand combinations are intended to fall within the scope of the presentdisclosure.

While the methods and systems described herein have been disclosed inconnection with certain preferred embodiments shown and described indetail, various modifications and improvements thereon may becomereadily apparent to those skilled in the art. Accordingly, the spiritand scope of the methods and systems described herein is not to belimited by the foregoing examples, but is to be understood in thebroadest sense allowable by law.

All documents referenced herein are hereby incorporated by reference.

What is claimed is:
 1. A method, comprising: determining a current flowthrough a motive electrical power path of a vehicle; directing thecurrent flow through a current protection circuit having a parallelarrangement, with a pyro-fuse on a first leg of the current protectioncircuit and a thermal fuse on a second leg of the current protectioncircuit; and providing a pyro-fuse activation command in response to thecurrent flow exceeding a threshold current flow value.
 2. The method ofclaim 1, further comprising configuring a first resistance through thefirst leg and a second resistance through the second leg such that aresulting current through the second leg after the pyro-fuse activatesis sufficient to activate the thermal fuse.
 3. The method of claim 1,further comprising configuring a second resistance through the secondleg such that a resulting current through the second leg after thepyro-fuse activates is below a second threshold current flow value. 4.The method of claim 1, further comprising a contactor coupled in aseries arrangement with the thermal fuse and providing a contactor opencommand in response to the current flow exceeding the threshold currentflow value.
 5. The method of claim 4, wherein the providing thecontactor open command is performed before the providing the pyro-fuseactivation command.
 6. The method of claim 1, further comprisingproviding a resistor coupled in a series arrangement with the pyro-fusesuch that a resulting current through the first leg after the thermalfuse activates is below a second threshold current flow value.
 7. Themethod of claim 1, further comprising providing a second thermal fusecoupled in a series arrangement with the pyro-fuse, such that aresulting current through the first leg after the thermal fuse activatesis sufficient to activate the second thermal fuse.
 8. An apparatus,comprising: a current protection circuit structured with a pyro-fuse ona first leg of the current protection circuit and a thermal fuse on asecond leg of the current protection circuit; a current detectioncircuit structured to determine a current flow through the currentprotection circuit; and a pyro-fuse activation circuit structured toprovide a pyro-fuse activation command in response to the current flowexceeding a threshold current flow value, wherein the pyro-fuse isresponsive to the pyro-fuse activation command.
 9. The apparatus ofclaim 8, further comprising a resistor coupled in a series arrangementwith the pyro-fuse, such that a resulting current through the second legafter the pyro-fuse activates is sufficient to activate the thermalfuse.
 10. The apparatus of claim 8, further comprising a contactorcoupled in a series arrangement with the thermal fuse, and a contactoractivation circuit structured to provide a contactor open command inresponse to the current flow exceeding the threshold current flow value.11. The apparatus of claim 8, wherein the contactor activation circuitis further structured to provide the contactor open command before thepyro-fuse activation circuit provides the pyro-fuse activation command.12. The apparatus of claim 10, wherein a resistor is in series with thecontactor to reduce the current through the second leg relative to thecurrent through the first leg.
 13. The apparatus of claim 8, wherein thepyro-fuse activation command activates and opens the second leg uponcommand.
 14. The apparatus of claim 8, wherein a first resistancethrough the first leg and a second resistance through the second leg areconfigured such that a resulting current through the second leg afterthe pyro-fuse activates is sufficient to activate the thermal fuse. 15.The apparatus of claim 8, wherein an opening of the second leg willcause the current in the first leg to increase and activate the thermalfuse.
 16. The apparatus of claim 8, wherein a resistor is coupled in aseries arrangement with the thermal fuse, such that a resulting currentthrough the second leg after the pyro-fuse activates is below a secondthreshold current flow value.
 17. A system, comprising: a vehicle havinga motive electrical power path; a power distribution unit having acurrent protection circuit disposed in the motive electrical power path,the current protection circuit comprising: a first leg of the currentprotection circuit comprising a first pyro-fuse; a second leg of thecurrent protection circuit comprising a thermal fuse in seriesarrangement with a second pyro-fuse; and wherein the first leg and thesecond leg are coupled in a parallel arrangement; a controller,comprising: a current detection circuit structured to determine acurrent flow through the motive electrical power path; and a pyro-fuseactivation circuit structured to provide a pyro-fuse activation commandin response to the current flow exceeding a threshold current flowvalue; and wherein at least one of the first pyro-fuse and the secondpyro-fuse is responsive to the pyro-fuse activation command.
 18. Thesystem of claim 17, further comprising a resistor coupled in a seriesarrangement with each of the thermal fuse and the second pyro-fuse, suchthat a resulting current through the second leg after the secondpyro-fuse activates is below a second threshold current flow value. 19.The system of claim 17, further comprising a resistor coupled in aseries arrangement with each of the thermal fuse and the secondpyro-fuse, such that a resulting current through the second leg afterthe second pyro-fuse activates sufficient to activate the thermal fuse.20. The system of claim 17, further comprising a contactor coupled in aseries arrangement with the thermal fuse and the second pyro-fuse, thecontroller further comprising a contactor activation circuit structuredto provide a contactor open command in response to the current flowexceeding the threshold current flow value.
 21. The system of claim 20,wherein the contactor activation circuit is further structured toprovide the contactor open command before the pyro-fuse activationcircuit provides the pyro-fuse activation command.
 22. A method,comprising: determining a current flow through a motive electrical powerpath of a vehicle; directing the current flow through a currentprotection circuit having a parallel arrangement, with a first pyro-fuseon a first leg of the current protection circuit and a thermal fuse inseries arrangement with a second pyro fuse on a second leg of thecurrent protection circuit; and providing a pyro-fuse activation commandin response to the current flow exceeding a threshold current flowvalue.
 23. The method of claim 22, further providing a contactor coupledin a series arrangement with the thermal fuse and the second pyro-fuseand a contactor activation circuit providing a contactor open command inresponse to the current flow exceeding the threshold current flow value.24. The method of claim 23, wherein providing the contactor open commandis performed before the providing the pyro-fuse activation command.